Physiological monitoring methods

ABSTRACT

A method of monitoring a subject includes attaching a sensor module having at least one optical emitter and detector to a body of the subject, delivering light from the at least one optical emitter into the body of the subject via a first light guide that is in optical communication with the at least one optical emitter, and collecting light from the body of the subject via a second light guide that is in optical communication with the at least one optical detector. The first light guide has a proximal end optically coupled to the at least one optical emitter and delivers light from the at least one optical emitter via a distal end thereof. The second light guide has a proximal end optically coupled to the at least one optical detector and collects light from the body of the subject via the distal end thereof.

RELATED APPLICATIONS

This application is a continuation application of U.S. patentapplication Ser. No. 13/715,247, filed Dec. 14, 2012, which is acontinuation-in-part of U.S. patent application Ser. No. 12/691,388,filed Jan. 21, 2010, now U.S. Pat. No. 8,700,111, which claims thebenefit of and priority to U.S. Provisional Patent Application No.61/208,567 filed Feb. 25, 2009, U.S. Provisional Patent Application No.61/208,574 filed Feb. 25, 2009, U.S. Provisional Patent Application No.61/212,444 filed Apr. 13, 2009, and U.S. Provisional Patent ApplicationNo. 61/274,191 filed Aug. 14, 2009, the disclosures of which areincorporated herein by reference as if set forth in their entireties.

FIELD OF THE INVENTION

The present invention relates generally to headsets and, moreparticularly, to headset earbuds.

BACKGROUND OF THE INVENTION

There is growing market demand for personal health and environmentalmonitors, for example, for gauging overall health and metabolism duringexercise, athletic training, dieting, daily life activities, sickness,and physical therapy. However, traditional health monitors andenvironmental monitors may be bulky, rigid, and uncomfortable—generallynot suitable for use during daily physical activity. There is alsogrowing interest in generating and comparing health and environmentalexposure statistics of the general public and particular demographicgroups. For example, collective statistics may enable the healthcareindustry and medical community to direct healthcare resources to wherethey are most highly valued. However, methods of collecting thesestatistics may be expensive and laborious, often utilizing human-basedrecording/analysis steps at multiple sites.

As such, improved ways of collecting, storing and analyzingphysiological information are needed. In addition, improved ways ofseamlessly extracting physiological information from a person duringeveryday life activities, especially during high activity levels, may beimportant for enhancing fitness training and healthcare quality,promoting and facilitating prevention, and reducing healthcare costs.

SUMMARY

It should be appreciated that this Summary is provided to introduce aselection of concepts in a simplified form, the concepts being furtherdescribed below in the Detailed Description. This Summary is notintended to identify key features or essential features of thisdisclosure, nor is it intended to limit the scope of the invention.

According to some embodiments of the present invention, a headsetconfigured to be attached to the ear of a person includes a base, anearbud housing extending outwardly from the base that is configured tobe positioned within an ear of a subject, and a cover surrounding theearbud housing. The base includes a speaker, an optical emitter, and anoptical detector. The cover includes light transmissive material that isin optical communication with the optical emitter and the opticaldetector and serves as a light guide to deliver light from the opticalemitter into the ear canal of the subject wearing the headset at one ormore predetermined locations and to collect light external to the earbudhousing and deliver the collected light to the optical detector. Theoptical emitter, via the light-guiding cover, directs optical energytowards a particular region of ear and the optical detector detectssecondary optical energy emanating from the ear region. In someembodiments, the optical detector may include an optical filterconfigured to pass secondary optical energy at selective wavelengths. Insome embodiments, the light transmissive material of the cover may beconfigured, for example via the use of cladding and/or light reflectivematerial, such that the cover serves as a light guide that is coupled inparallel to the optical emitter and detector. In some embodiments, thelight transmissive material of the cover may be configured, for examplevia the use of cladding and/or light reflective material, such that thecover serves as a light guide that is coupled perpendicular to theoptical emitter and detector.

In some embodiments, the headset may include various electroniccomponents secured to the base. For example, the headset may include oneor more environmental sensors configured to detect and/or measureenvironmental conditions in a vicinity of the headset. The headset mayinclude a signal processor configured to receive and process signalsproduced by the optical detector. For example, in some embodiments, asignal processor may be configured to extract secondary optical energyand remove optical noise or environmental noise. The headset may includea signal processor configured to receive and process signals produced bythe one or more environmental sensors. In addition, the headset mayinclude a transmitter configured to transmit signals processed by thesignal processor to a remote device in real time. Headsets according toembodiments of the present invention may utilize, for example,Bluetooth®, Wi-Fi, ZigBee, or other wireless transmitters.

In some embodiments, a housing is secured to and overlies the base so asto enclose and protect the speaker, optical emitter and opticaldetector, as well as other electronic components secured to the base(e.g., sensors, processor, transmitter etc.).

The earbud housing is in acoustical communication with the speaker andhas at least one aperture through which sound from the speaker can pass.The light-guiding cover surrounding the earbud housing also includes atleast one aperture through which sound from the speaker can pass. Thecover may be formed from a soft, resilient material, such as siliconewhich deforms when inserted within an ear canal of a subject. In someembodiments, the cover includes an alignment member that facilitatesalignment of the earbud housing within an ear canal of a subject.

Light directed into the ear of a subject from a light emitter and thesubsequent collection of light at a light detector, according toembodiments of the present invention, may be utilized for detectingand/or measuring, among other things, body temperature, skintemperature, blood gas levels, muscle tension, heart rate, blood flow,cardiopulmonary functions, etc.

In some embodiments of the present invention, the light-guiding covermay include a lens that is in optical communication with the opticalemitter and/or optical detector. The lens may be configured to focuslight emitted by the optical emitter and/or to focus collected lighttoward the optical detector. In some embodiments, multiple lenses may beincorporated into a light-guiding cover.

In some embodiments, the light-guiding cover may include a lightdiffusion region in optical communication with the light transmissivematerial that diffuses light emitted by the optical detector.

In some embodiments, the light-guiding cover may include aluminescence-generating region, such as a phosphor-containing region,that is in optical communication with the light transmissive material.The luminescence-generating region may be embedded within thelight-guiding cover and/or on a surface of the light-guiding cover. Theluminescence-generating region is configured to receive light emitted bythe optical emitter and convert at least a portion of the received lightto light having a different wavelength from that of the received light.

In some embodiments, the light-guiding cover includes one or moregrooves formed therein. Each groove is configured to direct externallight to the optical detector.

In some embodiments, the light transmissive material of thelight-guiding cover is configured to direct light from the opticalemitter to a plurality of locations at an outer surface of the cover fordelivery into an ear canal of a subject.

In some embodiments, the light transmissive material of thelight-guiding cover is a translucent material or includes translucentmaterial in selected locations.

In some embodiments, a light reflective material is on at least aportion of one or both of the inner and outer surfaces of thelight-guiding cover.

According to some embodiments of the present invention, a light-guidingearbud for a headset includes light transmissive material that is inoptical communication with an optical emitter and optical detectorassociated with the headset. The light transmissive material isconfigured to deliver light from the optical emitter into the ear canalof a subject at one or more predetermined locations and to collect lightexternal to the earbud housing and deliver the collected light to theoptical detector. In some embodiments, the light emitter and lightdetector may be integral with the earbud. For example, in someembodiments, a flexible optical emitter is incorporated within theearbud and is in optical communication with the light transmissivematerial.

In some embodiments, an earbud includes at least one lens in opticalcommunication with the light transmissive material. Each lens may beconfigured to focus light from the optical emitter onto one or morepredetermined locations in the ear of a subject and/or to focuscollected external light onto the optical detector.

In some embodiments of the present invention, an earbud may includeluminescent material. Luminescent light is generated from opticalexcitation of the luminescent material by an optical emitter.

In some embodiments of the present invention, an earbud may integrate asensor module containing a plurality of sensor elements for measuringphysiological information and at least one noise source for measuringnoise information. A “noise source”, as used herein, refers to a sensor,such as an optical sensor, inertial sensor, electrically conductivesensor, capacitive sensor, inductive sensor, etc., and derives it namefrom the fact that it is a source of input to a filter, such as anadaptive filter described below.

The physiological sensors of the sensor module may generate a signalthat includes physiological information plus noise information. Thenoise may be removed by combining the physiological information andnoise information from the sensor module with noise information from thenoise source of the sensor module via an electronic filtering method,such as a signal processing technique. Specific examples of such signalprocessing techniques include FIR (Finite Impulse Response), IIR(Infinite Impulse Response), informatics, machine learning, and adaptivefilter methods. The output of the adaptive filter may be a physiologicalsignal that is wholly or partially free of noise. In some embodiments,motion-related noise from a subject activity such as running may beremoved from the physiological plus noise signal generated by aphotoplethysmography (PPG) sensor for measuring blood constituent levelsor blood flow properties, such as blood oxygen level, VO₂, or heartrate.

In some embodiments of the present invention, the noise source input ofan adaptive filter may include a “blocked channel” of optical energy, aninertial sensor, or environmental energy. In some embodiments, theenvironmental energy may be unwanted ambient optical noise.

In some embodiments of the present invention, a processor/multiplexorprocesses physiological signals and noise signals into a data string.This data string may contain information relating to physiologicalinformation and motion-related information. The processing method mayinclude signal processing techniques such as pre-adaptive signalconditioning, adaptive filtering, and parameter extraction.

In some embodiments, an earbud includes one or more sensor modules thatincludes one or more sensors for sensing physiological information andenvironmental information, such as noise, for example. As such, theearbud may function as a physiological monitor as well as anenvironmental monitor. In some embodiments, the earbud may include amicroprocessor that is in electrical communication with the sensormodule(s). For example, a microprocessor incorporated into an earbud maybe configured to execute an adaptive filter algorithm to remove noisefrom at least one signal generated by a sensor module in the earbud. Amicroprocessor may also be configured to process information from theone or more sensors to generate a digital output string, wherein thedigital output string includes a plurality of physiological andmotion-related information.

Physiological sensors that may be incorporated into headsets and/orearbuds, according to some embodiments of the present invention, may beconfigured to detect and/or measure one or more of the following typesof physiological information: heart rate, pulse rate, breathing rate,blood flow, VO₂, VO₂max, heartbeat signatures, cardio-pulmonary health,organ health, metabolism, electrolyte type and/or concentration,physical activity, caloric intake, caloric metabolism, blood metabolitelevels or ratios, blood pH level, physical and/or psychological stresslevels and/or stress level indicators, drug dosage and/or dosimetry,physiological drug reactions, drug chemistry, biochemistry, positionand/or balance, body strain, neurological functioning, brain activity,brain waves, blood pressure, cranial pressure, hydration level,auscultatory information, auscultatory signals associated withpregnancy, physiological response to infection, skin and/or core bodytemperature, eye muscle movement, blood volume, inhaled and/or exhaledbreath volume, physical exertion, exhaled breath physical and/orchemical composition, the presence and/or identity and/or concentrationof viruses and/or bacteria, foreign matter in the body, internal toxins,heavy metals in the body, anxiety, fertility, ovulation, sex hormones,psychological mood, sleep patterns, hunger and/or thirst, hormone typeand/or concentration, cholesterol, lipids, blood panel, bone density,organ and/or body weight, reflex response, sexual arousal, mental and/orphysical alertness, sleepiness, auscultatory information, response toexternal stimuli, swallowing volume, swallowing rate, sickness, voicecharacteristics, voice tone, voice pitch, voice volume, vital signs,head tilt, allergic reactions, inflammation response, auto-immuneresponse, mutagenic response, DNA, proteins, protein levels in theblood, water content of the blood, pheromones, internal body sounds,digestive system functioning, cellular regeneration response, healingresponse, stem cell regeneration response, etc.

Environmental sensors that may be incorporated into headsets and/orearbuds, according to some embodiments of the present invention, may beconfigured to detect and/or measure one or more of the following typesof environmental information: climate, humidity, temperature, pressure,barometric pressure, soot density, airborne particle density, airborneparticle size, airborne particle shape, airborne particle identity,volatile organic chemicals (VOCs), hydrocarbons, polycyclic aromatichydrocarbons (PAHs), carcinogens, toxins, electromagnetic energy,optical radiation, X-rays, gamma rays, microwave radiation, terahertzradiation, ultraviolet radiation, infrared radiation, radio waves,atomic energy alpha particles, atomic energy beta-particles, gravity,light intensity, light frequency, light flicker, light phase, ozone,carbon monoxide, carbon dioxide, nitrous oxide, sulfides, airbornepollution, foreign material in the air, viruses, bacteria, signaturesfrom chemical weapons, wind, air turbulence, sound and/or acousticalenergy, ultrasonic energy, noise pollution, human voices, animal sounds,diseases expelled from others, exhaled breath and/or breath constituentsof others, toxins from others, pheromones from others, industrial and/ortransportation sounds, allergens, animal hair, pollen, exhaust fromengines, vapors and/or fumes, fuel, signatures for mineral depositsand/or oil deposits, snow, rain, thermal energy, hot surfaces, hotgases, solar energy, hail, ice, vibrations, traffic, the number ofpeople in a vicinity of the person, coughing and/or sneezing sounds frompeople in the vicinity of the person, loudness and/or pitch from thosespeaking in the vicinity of the person.

According to some embodiments of the present invention, earbuds forheadsets may include a chipset having at least one sensor element, noisesource element, signal processor, input/output line, digital control,and power regulator.

Light-guiding earbuds according to the various embodiments of thepresent invention may be utilized with mono headsets (i.e., headsetshaving one earbud) as well as stereo headsets (i.e., headsets having twoearbuds). Additionally, the light-guiding region of earbuds, accordingto embodiments of the present invention, may be integrated not only intoan earbud cover and earbud housing, but also into each or all componentsof an earbud. Moreover, light-guiding earbuds according to the variousembodiments of the present invention may be utilized with hearing aids,body jewelry, or any other attachment that can be placed near the headregion, such as eye glasses or shades, a headband, a cap, helmet, visor,or the like.

According to some embodiments of the present invention, a monitoringdevice includes a circular band capable of encircling a finger of asubject, and a base having an optical emitter and an optical detectorattached to the circular band. The circular band includes lighttransmissive material in optical communication with the optical emitterand optical detector that is configured to deliver light from theoptical emitter to one or more portions of the finger of the subject andto collect light from one or more portions of the finger of the subjectand deliver the collected light to the optical detector. In someembodiments, the circular band includes first and second concentric bodyportions.

In some embodiments, the circular band includes a lens region in opticalcommunication with the optical emitter that focuses light emitted by theoptical emitter and/or that collects light reflected from a finger. Insome embodiments the circular band includes a phosphor-containing regionin optical communication with the light transmissive material, whereinthe phosphor-containing region receives light emitted by the opticalemitter and converts at least a portion of the received light to lighthaving a different wavelength from the received light.

In some embodiments, the light transmissive material of the circularband has an outer surface and an inner surface, and a cladding material,such as light reflective material, is on (or near) at least a portion ofone or both of the inner and outer surfaces.

In some embodiments, the base includes one or more of the following: asignal processor configured to receive and process signals produced bythe optical detector, a transmitter configured to transmit signalsprocessed by the signal processor to a remote device.

According to some embodiments of the present invention, a monitoringdevice configured to be attached to the body of a subject includes abase having an optical emitter and an optical detector, and lighttransmissive material attached to the base. The light transmissivematerial is in optical communication with the optical emitter andoptical detector and is configured to deliver light from the opticalemitter to one or more portions of the body of the subject and tocollect light from one or more portions of the body of the subject anddeliver the collected light to the optical detector. The lighttransmissive material may include adhesive material in one or morelocations that is configured to adhesively secure the device to the bodyof the subject.

In some embodiments, an outer body portion is attached to the base andto the light transmissive material. The outer body portion may includeadhesive material in one or more locations that is configured toadhesively secure the device to the body of the subject.

In some embodiments, the light transmissive material includes a lensregion that is in optical communication with the optical emitter andthat focuses light emitted by the optical emitter and/or that collectslight reflected from a finger. In some embodiments, the lighttransmissive material includes a phosphor-containing region thatreceives light emitted by the optical emitter and converts at least aportion of the received light to light having a different wavelengthfrom the received light. In some embodiments, the light transmissivematerial has an outer surface and an inner surface, and a lightreflective material is disposed on or near at least a portion of one orboth of the inner and outer surfaces.

In some embodiments, the base includes one or more of the following: asignal processor configured to receive and process signals produced bythe optical detector, a transmitter configured to transmit signalsprocessed by the signal processor to a remote device.

According to some embodiments of the present invention, a headsetincludes a housing that is configured to be positioned within an ear ofa subject, an optical emitter, an optical detector, and at least onelight guide associated with the housing. The headset may include aspeaker disposed within the housing, and the housing may include atleast one aperture through which sound from the speaker can pass. Theheadset may also include a signal processor that is configured toreceive and process signals produced by the optical detector.

The at least one light guide includes a distal end that is configured toengage (or be positioned adjacent) a portion of the ear of the subject.An opposite end of the at least one light guide is in opticalcommunication the optical emitter or optical detector. As such, the atleast one light guide is configured to deliver light from the opticalemitter into an ear region of the subject via the distal end or collectlight from an ear region of the subject via the distal end or delivercollected light to the optical detector. In some embodiments, theoptical emitter and optical detector may each have one or morerespective light guides in optical communication therewith.

In some embodiments, the at least one light guide has a distal endportion that extends outwardly from the housing. In other embodiments,the at least one light guide has a distal end portion that issubstantially flush with the housing or is recessed within the housing.

In some embodiments of the present invention, the optical emitter andoptical detector are attached to the housing, such as the housing of theearbud itself. In other embodiments, the optical emitter and/or opticaldetector are located remotely from the housing. For example, the opticalemitter and/or optical detector may be located on a headband, back-bar,back-band, ear hook, or any other structure that is a part of theheadset. Moreover, the optical emitter and optical detector may belocated at different respective locations anywhere on the headset. Theat least one light guide extends from the remotely located opticalemitter and/or optical detector and to the housing such that a distalend thereof can engage (or be positioned adjacent) a portion of the earof the subject.

The at least one light guide may be formed from various types of lighttransmissive material, typically with a refractive index of at least one(1), and may have various shapes and configurations. For example, insome embodiments, the at least one light guide has an elongated,generally cylindrical configuration. In some embodiments, the at leastone light guide comprises an elastomeric light transmissive material. Inother embodiments, the at least one light guide comprises asubstantially rigid light transmissive material. In some embodiments,the at least one light guide may be surrounded or partially surroundedby a cladding material that is configured to at least partially confinelight within the light guide and/or block light from an external sourcefrom entering the at least one light guide. The cladding material may bea light blocking material and/or a light reflective material, such as ablack or silver coating on one or more portions of the surface of the atleast one light guide.

In some embodiments, a light blocking material is positioned between theoptical emitter and detector such that the optical emitter and detectorare not in direct optical communication with each other.

In some embodiments, optical coupling material is applied to the opticalemitter and the at least one light guide is in optical communicationwith the optical emitter via the optical coupling material.

In some embodiments, optical coupling material is applied to the opticaldetector and the at least one light guide is in optical communicationwith the optical detector via the optical coupling material.

In some embodiments, a plurality of light guides are utilized, eachhaving a distal end that engages a respective different portion of theear of a subject.

In some embodiments, the headset includes a plurality of opticalemitters and a plurality of light guides. The plurality of light guidesare in optical communication with the plurality of optical emitters andare configured to deliver light from the plurality of optical emittersto an ear region of the subject.

In some embodiments, the headset includes a plurality of opticaldetectors and a plurality of light guides. The plurality of light guidesare in optical communication with the plurality of optical detectors andconfigured to collect light from an ear region of the subject anddeliver collected light to the plurality of optical detectors.

According to other embodiments of the present invention, a headsetincludes a housing configured to be positioned within an ear of asubject, an optical emitter, an optical detector, and first and secondlight guides associated with the housing. The headset may include aspeaker disposed within the housing, and the housing may include atleast one aperture through which sound from the speaker can pass. Theheadset may also include a signal processor that is configured toreceive and process signals produced by the optical detector.

Each of the first and second light guides includes a distal end that isconfigured to engage (or be positioned adjacent) a respective portion ofthe ear of the subject. The first light guide is in opticalcommunication with the optical emitter and is configured to deliverlight from the optical emitter into an ear region of the subject via thefirst light guide distal end. The second light guide is in opticalcommunication with the optical detector and is configured to collectlight from an ear region of the subject via the second light guidedistal end and deliver collected light to the optical detector.

In some embodiments, the distal end of the first and/or second lightguides extends outwardly from the housing. In other embodiments, thedistal end of the first and/or second light guides is substantiallyflush with the housing or is recessed within the housing.

In some embodiments of the present invention, the optical emitter andoptical detector are attached to the housing. In other embodiments, theoptical emitter and/or optical detector are located remotely from thehousing. For example, the optical emitter and optical detector may belocated on a headband or other structure that is a part of the headset.The first and second light guides extend from the remotely locatedoptical emitter and optical detector and to the housing such that adistal end of each can engage (or be positioned adjacent) a respectiveportion of the ear of the subject.

The first and second light guides may be formed from various types oflight transmissive material, typically with a refractive index of atleast one (1), and may have various shapes and configurations. Forexample, in some embodiments, one or both of the first and second lightguides have an elongated, generally cylindrical configuration. In someembodiments, one or both of the first and second light guides maycomprise an elastomeric light transmissive material. In otherembodiments, one or both of the first and second light guides maycomprise a substantially rigid light transmissive material. Examples ofsuitable soft or elastomeric materials may include, but are not limitedto, silicone, rubber, polymer-based materials, latex, lower durometerplastics, and the like. Examples of suitable rigid materials mayinclude, but are not limited to, polyurethane, polymer-based materials,resins, higher durometer plastics, polycarbonate, acrylic, and the like.

In some embodiments, one or both of the first and second light guidesmay be surrounded or may be partially surrounded by a cladding materialthat is configured to block light from an external source and/or atleast partially confine light within one or both of the first and secondlight guides. The cladding material may be a light blocking materialand/or a light reflective material. In some embodiments, the claddingmaterial may be a coating, such as a black, mylar, gold, or silvercoating, or a textured surface, on one or more portions of the surfaceof the first and second light guides. In some embodiments, the claddingmay be a texturized or specially treated surface of the light guideitself, such as a micro- or nano-structured surface or anelectrochemically or chemically treated surface. Surface texturing canbe used to scatter internal light back within the light guide or toscatter external light away from the light guide.

In some embodiments, the light guide may also be and/or comprise anoptical filter. This may provide a structure that provides both lightguiding of the desired wavelengths and light blocking of undesiredwavelengths. For example, the light-guide may comprise a material havingan optically filtering dye or a material which inherently filters one ormore wavelengths of light. For example, a light-absorptive dye, many ofwhich are well-known in the art, may be integrated within or coated ontop a polycarbonate or acrylic sheet. Similarly, a light-absorptive dyemay be integrated within a resin which may then be molded into one ormore light guides. A few non-limiting examples of an inherentlyfiltering material includes sapphire, which absorbs some infrared (IR)wavelengths, or glass, which absorbs some ultraviolet (UV) wavelengths.However, various types of filtering material may be utilized, withoutlimitation.

According to other embodiments of the present invention, a headsetincludes a housing configured to be positioned within an ear of asubject, an optical emitter, an optical detector, and a light guideassociated with the housing. The headset may include a speaker disposedwithin the housing, and the housing may include at least one aperturethrough which sound from the speaker can pass. The headset may alsoinclude

a signal processor that is configured to receive and process signalsproduced by the optical detector.

The light guide includes a distal end that is configured to engage (orbe positioned adjacent) a portion of the ear of the subject. An oppositeend of the light guide is in optical communication with the opticalemitter and the optical detector. As such, the light guide is configuredto deliver light from the optical emitter into an ear region of thesubject via the light guide distal end, and to collect light from theear region of the subject via the light guide distal end and delivercollected light to the optical detector.

In some embodiments, the light guide has a distal end portion thatextends outwardly from the housing. In other embodiments, the lightguide has a distal end portion that is substantially flush with thehousing or is recessed within the housing.

In some embodiments of the present invention, the optical emitter andoptical detector are attached to the housing. In other embodiments, theoptical emitter and/or optical detector are located remotely from thehousing. For example, the optical emitter and/or optical detector may belocated on a headband or any other structure that is a part of theheadset. Moreover, the optical emitter and optical detector may belocated at different respective locations anywhere on the headset. Thelight guide extends from the remotely located optical emitter andoptical detector and to the housing such that a distal end thereof canengage (or be positioned adjacent) a portion of the ear of the subject.

The light guide may be formed from various types of light transmissivematerial, typically with a refractive index of at least one (1), and mayhave various shapes and configurations. For example, in someembodiments, the light guide has an elongated, generally cylindricalconfiguration. In some embodiments, the light guide comprises anelastomeric light transmissive material. In other embodiments, the lightguide comprises a substantially rigid light transmissive material. Insome embodiments, the light guide may be surrounded or partiallysurrounded by a cladding material that is configured to block light froman external source from entering the at least one light guide and/or atleast partially confine light within the light guide. The claddingmaterial may be a light blocking material and/or a light reflectivematerial, such as a black or silver coating on one or more portions ofthe surface of the light guide.

According to other embodiments of the present invention, a wearablesensor module includes a housing configured to be worn by a subject, anoptical emitter, an optical detector, and at least one light guideextending outwardly from the housing. The at least one light guideincludes a distal end that is configured to engage (or be positionedadjacent) a skin region of the subject. An opposite end of the at leastone light guide is in optical communication with the optical emitter oroptical detector. As such, the at least one light guide is configured todeliver light from the optical emitter into a skin region the subjectvia the distal end or collect light from a skin region of the subjectvia the distal end and deliver collected light to the optical detector.In some embodiments, the optical emitter and optical detector may eachhave one or more respective light guides in optical communicationtherewith.

In some embodiments of the present invention, the optical emitter andoptical detector are attached to the housing. In other embodiments, theoptical emitter and/or optical detector are located remotely from thehousing.

The at least one light guide may be formed from various types of lighttransmissive material, typically with a refractive index of at least one(1), and may have various shapes and configurations. For example, insome embodiments, the at least one light guide has an elongated,generally cylindrical configuration. In some embodiments, the at leastone light guide comprises an elastomeric light transmissive material. Inother embodiments, the at least one light guide comprises asubstantially rigid light transmissive material. In some embodiments,the at least one light guide may be surrounded or partially surroundedby a cladding material that is configured to block light from anexternal source from entering the at least one light guide and/or atleast partially confine light within the at least one light guide.

In some embodiments, light blocking material is positioned between theoptical emitter and detector such that the optical emitter and detectorare not in direct optical communication with each other.

In some embodiments, optical coupling material is applied to the opticalemitter and the at least one light guide is in optical communicationwith the optical emitter via the optical coupling material.

In some embodiments, optical coupling material is applied to the opticaldetector and the at least one light guide is in optical communicationwith the optical detector via the optical coupling material.

It is noted that aspects of the invention described with respect to oneembodiment may be incorporated in a different embodiment although notspecifically described relative thereto. That is, all embodiments and/orfeatures of any embodiment can be combined in any way and/orcombination. Applicant reserves the right to change any originally filedclaim or file any new claim accordingly, including the right to be ableto amend any originally filed claim to depend from and/or incorporateany feature of any other claim although not originally claimed in thatmanner. These and other objects and/or aspects of the present inventionare explained in detail below.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which form a part of the specification,illustrate various embodiments of the present invention. The drawingsand description together serve to fully explain embodiments of thepresent invention.

FIG. 1 is an exploded perspective view of a headset with a light-guidingearbud, according to some embodiments of the present invention.

FIG. 2 is a perspective view of a stereo headset incorporatinglight-guiding earbuds, according to some embodiments of the presentinvention.

FIG. 3 is a side section view of a light-guiding earbud for a headset,according to some embodiments of the present invention.

FIGS. 4A-4D are side section views of light-guiding earbuds for aheadset, according to some embodiments of the present invention.

FIG. 5 is a side section view of a light-guiding earbud for a headset,according to some embodiments of the present invention.

FIG. 6 is a side section view of a light-guiding earbud for a headset,according to some embodiments of the present invention.

FIG. 7A is a side section view of a light-guiding earbud for a headset,according to some embodiments of the present invention.

FIG. 7B is a perspective view of a flexible optical emitter utilized inthe earbud of FIG. 7A, according to some embodiments of the presentinvention.

FIG. 8A is a side section view of a light-guiding earbud for a headset,according to some embodiments of the present invention.

FIG. 8B is a cross-sectional view of the earbud of FIG. 8A taken alonglines 8B-8B.

FIG. 8C is a side section view of a light-guiding earbud for a headset,according to some embodiments of the present invention.

FIG. 8D is a side section view of a light-guiding earbud for a headset,according to some embodiments of the present invention.

FIG. 9A is a side section view of a light-guiding earbud for a headset,according to some embodiments of the present invention.

FIG. 9B is a cross-sectional view of the earbud of FIG. 9A taken alonglines 9B-9B.

FIG. 9C illustrates luminescent particles within the earbud cover ofFIGS. 9A-9B, according to some embodiments of the present invention.

FIG. 9D is a side section view of a light-guiding earbud for a headset,according to some embodiments of the present invention.

FIG. 9E is a cross-sectional view of the earbud of FIG. 9D taken alonglines 9E-9E.

FIG. 10 illustrates various anatomy of a human ear.

FIG. 11A is a side section view of a light-guiding earbud for a headset,according to some embodiments of the present invention.

FIG. 11B is a cross-sectional view of the earbud of FIG. 11A taken alonglines 11B-11B.

FIGS. 12A-12B illustrate respective opposite sides of a sensor modulethat may be located near the periphery of an earbud, according to someembodiments of the present invention.

FIG. 13 illustrates an adaptive filter and noise source for removingnoise from a noisy physiological signal, according to some embodimentsof the present invention.

FIGS. 14A-14D are respective graphs of time-dependent data collectedfrom a light-guiding earbud worn by a person, according to someembodiments of the present invention.

FIG. 15 is a graph of processed physiological signal data from a headsethaving one or more light-guiding earbuds, according to some embodimentsof the present invention.

FIG. 16 is a flow chart of operations for extracting physiologicalinformation from headset sensor signals, according to some embodimentsof the present invention.

FIG. 17 is a block diagram that illustrates sensor signals beingprocessed into a digital data string including activity data andphysiological data, according to some embodiments of the presentinvention.

FIG. 18 illustrates a digital data string, according to some embodimentsof the present invention.

FIG. 19 illustrates the optical interaction between the sensor module ofFIGS. 12A-12B and the skin of a subject.

FIG. 20 illustrates a chipset for use in a headset, according to someembodiments of the present invention.

FIG. 21 illustrates a chipset for use in a stereo headset, according tosome embodiments of the present invention.

FIG. 22A is a top plan view of a monitoring device configured to beattached to finger of a subject, according to some embodiments of thepresent invention.

FIG. 22B is a cross-sectional view of the monitoring device of FIG. 22Ataken along lines 22B-22B.

FIG. 23 is a side view of a monitoring device configured to be attachedto the body of a subject, according to some embodiments of the presentinvention.

FIGS. 24A and 24B are perspective views of a headset having light guidesextending from a housing thereof, according to some embodiments of thepresent invention, and wherein the light guides are in opticalcommunication with an optical emitter and optical detector.

FIGS. 25A and 25B are perspective views of a headset having light guidesextending from a housing thereof, according to some embodiments of thepresent invention, and wherein the light guides are in opticalcommunication with an optical emitter and optical detector.

FIGS. 26-29 are illustrate various light guide configurations that maybe utilized within headsets and sensor modules, according to someembodiments of the present invention.

FIG. 30 is an enlarged cross-sectional view of a light guide with alayer of cladding material surrounding the light guide, according tosome embodiments of the present invention.

FIG. 31 illustrates elongated light guides that may be utilized withheadsets and sensor modules, according to some embodiments of thepresent invention, such that an optical emitter and/or optical detectorcan be located remotely from the housing of a headset or sensor module.

FIG. 32 is a perspective view of a stereo headset wherein an opticalemitter and optical detector are located remotely from the earbuds andwherein light guides extend from the optical emitter and opticaldetector to an earbud, according to some embodiments of the presentinvention.

FIG. 33 is an enlarged perspective view of an earbud of the headset ofFIG. 32 and illustrating the exposed distal ends of the light guides ofFIG. 32.

FIG. 34 is a perspective view of a headset having light guides,according to some embodiments of the present invention, and wherein thelight guides are in optical communication with an optical emitter andoptical detector.

FIG. 35 is an exploded perspective view of a headset with an earbudhousing having a plurality of light guides associated therewith,according to some embodiments of the present invention.

FIG. 36 is a perspective view of a headset with an earbud housing havinglight guides associated therewith, according to some embodiments of thepresent invention.

FIG. 37 is a cross sectional view of the headset of FIG. 36 taken alonglines A-A.

FIG. 38 is an enlarged partial view of the headset of FIG. 37.

FIG. 39 is a perspective view of a headset with an earbud housing havinglight guides associated therewith, according to some embodiments of thepresent invention.

FIG. 40 is an exploded perspective view of the headset of FIG. 39.

DETAILED DESCRIPTION

The present invention will now be described more fully hereinafter withreference to the accompanying figures, in which embodiments of theinvention are shown. This invention may, however, be embodied in manydifferent forms and should not be construed as limited to theembodiments set forth herein. Like numbers refer to like elementsthroughout. In the figures, certain layers, components or features maybe exaggerated for clarity, and broken lines illustrate optionalfeatures or operations unless specified otherwise. In addition, thesequence of operations (or steps) is not limited to the order presentedin the figures and/or claims unless specifically indicated otherwise.Features described with respect to one figure or embodiment can beassociated with another embodiment or figure although not specificallydescribed or shown as such.

It will be understood that when a feature or element is referred to asbeing “on” another feature or element, it can be directly on the otherfeature or element or intervening features and/or elements may also bepresent. In contrast, when a feature or element is referred to as being“directly on” another feature or element, there are no interveningfeatures or elements present. It will also be understood that, when afeature or element is referred to as being “connected”, “attached” or“coupled” to another feature or element, it can be directly connected,attached or coupled to the other feature or element or interveningfeatures or elements may be present. In contrast, when a feature orelement is referred to as being “directly connected”, “directlyattached” or “directly coupled” to another feature or element, there areno intervening features or elements present. Although described or shownwith respect to one embodiment, the features and elements so describedor shown can apply to other embodiments. It will also be appreciated bythose of skill in the art that references to a structure or feature thatis disposed “adjacent” another feature may have portions that overlap orunderlie the adjacent feature.

The terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting of the invention. Asused herein, the singular forms “a”, “an” and “the” are intended toinclude the plural forms as well, unless the context clearly indicatesotherwise. It will be further understood that the terms “comprises”and/or “comprising,” when used in this specification, specify thepresence of stated features, steps, operations, elements, and/orcomponents, but do not preclude the presence or addition of one or moreother features, steps, operations, elements, components, and/or groupsthereof. As used herein, the term “and/or” includes any and allcombinations of one or more of the associated listed items.

Spatially relative terms, such as “under”, “below”, “lower”, “over”,“upper” and the like, may be used herein for ease of description todescribe one element or feature's relationship to another element(s) orfeature(s) as illustrated in the figures. It will be understood that thespatially relative terms are intended to encompass differentorientations of the device in use or operation in addition to theorientation depicted in the figures. For example, if a device in thefigures is inverted, elements described as “under” or “beneath” otherelements or features would then be oriented “over” the other elements orfeatures. Thus, the exemplary term “under” can encompass both anorientation of over and under. The device may be otherwise oriented(rotated 90 degrees or at other orientations) and the spatially relativedescriptors used herein interpreted accordingly. Similarly, the terms“upwardly”, “downwardly”, “vertical”, “horizontal” and the like are usedherein for the purpose of explanation only unless specifically indicatedotherwise.

It will be understood that although the terms first and second are usedherein to describe various features/elements, these features/elementsshould not be limited by these terms. These terms are only used todistinguish one feature/element from another feature/element. Thus, afirst feature/element discussed below could be termed a secondfeature/element, and similarly, a second feature/element discussed belowcould be termed a first feature/element without departing from theteachings of the present invention. Like numbers refer to like elementsthroughout.

Unless otherwise defined, all terms (including technical and scientificterms) used herein have the same meaning as commonly understood by oneof ordinary skill in the art to which this invention belongs. It will befurther understood that terms, such as those defined in commonly useddictionaries, should be interpreted as having a meaning that isconsistent with their meaning in the context of the specification andrelevant art and should not be interpreted in an idealized or overlyformal sense unless expressly so defined herein. Well-known functions orconstructions may not be described in detail for brevity and/or clarity.

The term “headset”, as used herein, is intended to include any type ofdevice or earpiece that may be attached to or near the ear (or ears) ofa user and may have various configurations, without limitation. Headsetsincorporating light-guiding earbuds, as well as light guides, asdescribed herein may include mono headsets (a device having only oneearbud, one earpiece, etc.) and stereo headsets (a device having twoearbuds, two earpieces, etc.), earbuds, hearing aids, ear jewelry, facemasks, headbands, and the like. In some embodiments, the term “headset”may include broadly headset elements that are not located on the headbut are associated with the headset. For example, in a “medallion” stylewireless headset, where the medallion comprises the wireless electronicsand the headphones are plugged into or hard-wired into the medallion,the wearable medallion would be considered part of the headset as awhole. Similarly, in some cases, if a mobile phone or other mobiledevice is intimately associated with a plugged-in headphone, then theterm “headset” may refer to the headphone-mobile device combination.

The term “real-time” is used to describe a process of sensing,processing, or transmitting information in a time frame which is equalto or shorter than the minimum timescale at which the information isneeded. For example, the real-time monitoring of pulse rate may resultin a single average pulse-rate measurement every minute, averaged over30 seconds, because an instantaneous pulse rate is often useless to theend user. Typically, averaged physiological and environmentalinformation is more relevant than instantaneous changes. Thus, in thecontext of the present invention, signals may sometimes be processedover several seconds, or even minutes, in order to generate a“real-time” response.

The term “monitoring” refers to the act of measuring, quantifying,qualifying, estimating, sensing, calculating, interpolating,extrapolating, inferring, deducing, or any combination of these actions.More generally, “monitoring” refers to a way of getting information viaone or more sensing elements. For example, “blood health monitoring”includes monitoring blood gas levels, blood hydration, andmetabolite/electrolyte levels.

The term “physiological” refers to matter or energy of or from the bodyof a creature (e.g., humans, animals, etc.). In embodiments of thepresent invention, the term “physiological” is intended to be usedbroadly, covering both physical and psychological matter and energy ofor from the body of a creature. However, in some cases, the term“psychological” is called-out separately to emphasize aspects ofphysiology that are more closely tied to conscious or subconscious brainactivity rather than the activity of other organs, tissues, or cells.

The term “body” refers to the body of a subject (human or animal) thatmay wear a headset incorporating one or more light-guiding earbuds,according to embodiments of the present invention.

In the following figures, various headsets and light-guiding earbuds foruse with headsets will be illustrated and described for attachment tothe ear of the human body. However, it is to be understood thatembodiments of the present invention are not limited to those worn byhumans.

The ear is an ideal location for wearable health and environmentalmonitors. The ear is a relatively immobile platform that does notobstruct a person's movement or vision. Headsets located at an ear have,for example, access to the inner-ear canal and tympanic membrane (formeasuring core body temperature), muscle tissue (for monitoring muscletension), the pinna and earlobe (for monitoring blood gas levels), theregion behind the ear (for measuring skin temperature and galvanic skinresponse), and the internal carotid artery (for measuringcardiopulmonary functioning), etc. The ear is also at or near the pointof exposure to: environmental breathable toxicants of interest (volatileorganic compounds, pollution, etc.; noise pollution experienced by theear; and lighting conditions for the eye. Furthermore, as the ear canalis naturally designed for transmitting acoustical energy, the earprovides a good location for monitoring internal sounds, such asheartbeat, breathing rate, and mouth motion.

Wireless, Bluetooth®-enabled, and/or other personal communicationheadsets may be configured to incorporate physiological and/orenvironmental sensors, according to some embodiments of the presentinvention. As a specific example, Bluetooth® headsets are typicallylightweight, unobtrusive devices that have become widely acceptedsocially. Moreover, Bluetooth® headsets are cost effective, easy to use,and are often worn by users for most of their waking hours whileattending or waiting for cell phone calls. Bluetooth® headsetsconfigured according to embodiments of the present invention areadvantageous because they provide a function for the user beyond healthmonitoring, such as personal communication and multimedia applications,thereby encouraging user compliance. Exemplary physiological andenvironmental sensors that may be incorporated into a Bluetooth® orother type of headsets include, but are not limited to accelerometers,auscultatory sensors, pressure sensors, humidity sensors, color sensors,light intensity sensors, pressure sensors, etc.

Headsets, both mono (single earbud) and stereo (dual earbuds),incorporating low-profile sensors and other electronics, according toembodiments of the present invention, offer a platform for performingnear-real-time personal health and environmental monitoring in wearable,socially acceptable devices. The capability to unobtrusively monitor anindividual's physiology and/or environment, combined with improved usercompliance, is expected to have significant impact on future plannedhealth and environmental exposure studies. This is especially true forthose that seek to link environmental stressors with personal stresslevel indicators. The large scale commercial availability of thislow-cost device can enable cost-effective large scale studies. Thecombination of monitored data with user location via GPS data can makeon-going geographic studies possible, including the tracking ofinfection over large geographic areas. The commercial application of theproposed platform encourages individual-driven health maintenance andpromotes a healthier lifestyle through proper caloric intake andexercise.

Accordingly, some embodiments of the present invention combine apersonal communications headset device with one or more physiologicaland/or environmental sensors. Other embodiments may combinephysiological and/or environmental sensors into a headset device.

Optical coupling into the blood vessels of the ear may vary betweenindividuals. As used herein, the term “coupling” refers to theinteraction or communication between excitation light entering a regionand the region itself. For example, one form of optical coupling may bethe interaction between excitation light generated from within alight-guiding earbud and the blood vessels of the ear. In oneembodiment, this interaction may involve excitation light entering theear region and scattering from a blood vessel in the ear such that theintensity of scattered light is proportional to blood flow within theblood vessel. Another form of optical coupling may be the interactionbetween excitation light generated by an optical emitter within anearbud and the light-guiding region of the earbud. Thus, an earbud withintegrated light-guiding capabilities, wherein light can be guided tomultiple and/or select regions along the earbud, can assure that eachindividual wearing the earbud will generate an optical signal related toblood flow through the blood vessels. Optical coupling of light to aparticular ear region of one person may not yield photoplethysmographicsignals for each person. Therefore, coupling light to multiple regionsmay assure that at least one blood-vessel-rich region will beinterrogated for each person wearing the light-guiding earbud. Couplingmultiple regions of the ear to light may also be accomplished bydiffusing light from a light source within the earbud.

Embodiments of the present invention are not limited to headsets thatcommunicate wirelessly. In some embodiments of the present invention,headsets configured to monitor an individual's physiology and/orenvironment may be wired to a device that stores and/or processes data.In some embodiments, this information may be stored on the headsetitself. Furthermore, embodiments of the present invention are notlimited to earbuds. In some embodiments, the light-guiding structure maybe molded around another part of the body, such as a digit, finger, toe,limb, around the nose or earlobe, or the like. In other embodiments, thelight-guiding structure may be integrated into a patch, such as abandage that sticks on a person's body.

Referring to FIG. 1, a headset 10 according to some embodiments of thepresent invention is illustrated. The illustrated headset 10 includes abase 12, a headset housing 14, an earbud housing 16, and a cover 18 thatsurrounds the earbud housing 16. The base 12 includes a main circuitboard 20 that supports and/or is connected to various electroniccomponents. In the illustrated embodiment, a speaker 22, optical emitter24, optical detectors 26, and thermopile 28 (described below) aremounted onto a secondary circuit board 32 which is secured to the maincircuit board 20. The earbud housing surrounds the speaker 22, opticalemitter 24, optical detectors 26, and thermopile 28. Collectively, theearbud housing 16, cover 18, and various electronic components (e.g.,speaker 22, optical emitter 24, optical detectors 26, thermopile 28)located within the earbud housing 16 of the illustrated headset 10 maybe referred to as an earbud 30. The headset housing 14 is secured to thebase 12 and is configured to enclose and protect the various electroniccomponents mounted to the base (e.g., main circuit board 20 andcomponents secured thereto, etc.) from ambient interference (air,humidity, particulates, electromagnetic interference, etc).

Each optical detector 26 may be a photodiode, photodetector,phototransistor, thyristor, solid state device, optical chipset, or thelike. The optical emitter 24 may be a light-emitting diode (LED), laserdiode (LD), compact incandescent bulb, micro-plasma emitter, IRblackbody source, or the like. The speaker 22 may be a compact speaker,such as an inductive speaker, piezoelectric speaker, electrostaticspeaker, or the like. One or more microphones, such as electrets, MEMS,acoustic transducers, or the like, may also be located within theheadset housing or earbud housing to pick up speech, physiologicalsounds, and/or environmental sounds.

The main circuit board 20 and secondary circuit board 32 may alsosupport one or more sensor modules (not shown) that contain variousphysiological and/or environmental sensors. For example, a sensormodule, such as sensor module 70 illustrated in FIGS. 12A-12B, may beattached to the circuit boards 20, 32. The circuit boards 20, 32 alsomay include at least one signal processor (not shown), at least onewireless module (not shown) for communicating with a remote device,and/or at least one memory storage device (not shown). An exemplarywireless module may include a wireless chip, antenna, or RFID tag. Insome embodiments, the wireless module may include a low-range wirelesschip or chipset, such as a Bluetooth® or ZigBee chip. These electroniccomponents may be located on the main circuit board 20, or on anothercircuit board, such as the secondary circuit board 32, attached to themain circuit board.

Secondary circuit board 32 may also include a temperature sensor, suchas a thermopile 28 mounted thereto. The thermopile 28 is oriented so asto point towards the tympanic membrane within the ear of a subjectwearing the headset 10 through the acoustic orifices 34 a, 34 b in theearbud housing 16 and cover 18, respectively. The secondary circuitboard 32 may be in electrical contact with the main circuit board 20 viasoldering, connectors, wiring, or the like. A battery 36, such as alithium polymer battery or other portable battery, may be mounted to themain circuit board 20 and may be charged via a USB charge port 38.Although not shown in FIG. 1, an ear hook may be attached to the base 12or housing 14 to help stabilize the earbud 30 and headset 10 worn by asubject and such that the earbud 30 is consistently placed at the samelocation within the ear canal of a subject.

In the illustrated embodiment, the earbud housing 16 is in acousticalcommunication with the speaker 22 and includes an aperture 34 a throughwhich sound from the speaker 22 can pass. However, additional aperturesmay also be utilized. The cover 18 also includes at least one aperture34 b through which sound from the speaker 22 can pass. The thermopile 28is used as a heat sensor and measures thermal radiation from the ear ofa subject via the acoustic apertures 34 a, 34 b. Additional or othersensors may be in the location of the thermopile 28, aligned towards thetympanic membrane, to sense other forms of energy, such as acoustic,mechanical, chemical, optical, or nuclear energy from the tympanicmembrane region. For example, a photodetector may replace the thermopile28 to measure light scattering off the tympanic membrane.

The cover 18 includes light transmissive material in a portion 19thereof that is referred to as a light-guiding region. The lighttransmissive material in light-guiding region 19 is in opticalcommunication with the optical emitter 24 and detectors 26. The lighttransmissive material in light-guiding region 19 is configured todeliver light from the optical emitter 24 into an ear canal of thesubject at one or more predetermined locations and to collect lightexternal to the earbud 30 and deliver the collected light to the opticaldetectors 26. As such, the earbud 30 of the illustrated headset 10 isreferred to as a “light-guiding” earbud 30.

In some embodiments, the light transmissive material in thelight-guiding region 19 may include a lens (e.g., lens 18L illustratedin FIG. 6). The lens 18L is in optical communication with the opticalemitter 24 and/or with the optical detectors 26. For example, a lens 18Lmay be configured to focus light emitted by the optical emitter 24 ontoone or more portions of an ear and/or to focus collected light on thelight detectors 26. Lenses are described below with respect to FIGS.5-6.

In some embodiments, the earbud cover 18 may integrate a transparentlight-guiding layer, wherein air is utilized as a cladding layer. Forexample, the earbud cover 18 may include an optically transparentsilicone molded layer, and the earbud housing 16 may be removed suchthat a cladding layer is air. In some embodiments, the earbud housing 16may be closed, and the light-guiding region 19 may be integrated withinthe cover 18 or between the housing 16 and cover 18.

The illustrated cover 18 of FIG. 1 includes an alignment member 40 (alsoreferred to as a stabilization arm) that facilitates alignment of theearbud 30 within an ear canal of a subject. The alignment member 40 mayfacilitate stable measurements of optical scattered light from the earregion, which can be important for PPG measurements and tympanictemperature measurements.

In some embodiments, a light-guiding cover 18 is formed from a soft,resilient material, such as silicone, which deforms when inserted withinan ear canal of a subject. However, various materials may be utilizedfor light-guiding covers 18 and for serving as light guides depending onthe type of earbud desired for a particular use case, according toembodiments of the present invention. For example, in some embodiments,a light-guiding cover 18 may be formed from a substantially rigidmaterial such that the light-guiding earbud 30 is substantially rigid.For example, for a running use case, the runner may wish to have firmbut soft earbuds, such that the earbud may deform to some extent wheninserted into the ear. In such case, the light-guiding region may besilicone or other soft material and the outer cladding may be air, apolymer, plastic, or a soft material having a lower index of refractionthan silicone.

FIG. 2 illustrates a stereo headset 100 that utilizes two light-guidingearbuds 130, according to some embodiments of the present invention. Theheadset 100 also includes various sensor elements 132 located at severalregions in the stereo headset 100. A benefit of the stereo headset 100may be that the total number of sensors measuring the ear region may bedoubled; alternatively, the sensors in each earbud may be halved.Another benefit of the stereo headset is that it may enable stereo musicduring daily activities. Another benefit of the stereo headset is thatasymmetric physiological differences can be detected in the user bymeasuring each side of the user in real-time. For example, differencesin blood flow between right and left sides of a user may be detected,indicating changes in right/left brain activity, the onset of a stroke,localized inflammation, or the like.

Light-guiding earbuds according to various embodiments of the presentinvention will now be described with respect to FIGS. 3, 4A-4D, 5, 6,7A-7B, 8A-8D, 9A-9B, and 11A-11B. Referring initially to FIGS. 3-4, alight-guiding earbud 30 includes a base 50, an earbud housing 16extending outwardly from the base 50 that is configured to be positionedwithin an ear E of a subject, and a cover 18 that surrounds the earbudhousing 16. The earbud housing 16 is in acoustical communication with aspeaker 22 and includes at least one aperture 34 a through which soundfrom the speaker 22 can pass. The cover 18 includes at least oneaperture 34 b through which sound from the speaker 22 can pass, andincludes light transmissive material in optical communication with anoptical emitter 24 and detector 26.

The cover 18 includes cladding material 21 on an inner surface 18 bthereof and on an outer surface 18 a thereof, as illustrated. An endportion 18 f of the cover outer surface 18 a does not have claddingmaterial. As such, the cover 18 serves as a light guide that deliverslight from the optical emitter 24 through the end portion 18 f and intothe ear canal C of a subject at one or more predetermined locations andthat collects light external to the earbud housing 16 and delivers thecollected light to the optical detector 26. In the various embodimentsdescribed herein, the terms light guide and cover are intended to beinterchangeable. However, it should be noted that, in other embodiments,the earbud housing 16 may also serve as a light guide without the needfor cover 18.

The base 50 in all of the earbud embodiments (FIGS. 3, 4A-4D, 5, 6,7A-7B, 8A-8D, 9A-9B, 11A-11B, 24A-24B, 25A-25B, 26-29, 31, and 34)described herein may include any combination of a printed circuit board,electrical connectors, and housing component for a headset. For example,the base 50 in FIGS. 3-6, 7A-7B, 8A-8D, 9A-9B, 11A-11B, 24A-24B,25A-25B, 26-29, 31, and 34 may include, for example, the base 12 of theheadset 10 of FIG. 1, the main circuit board 20 of the headset 10 ofFIG. 1, the housing 14 of the headset 10 of FIG. 1, or may be acombination of the base 12, main circuit board 20, and/or housing 14 ofthe headset 10 of FIG. 1.

The optical emitter 24 generates inspection light 111 and thelight-guiding region 19 of the light guide 18 directs the inspectionlight 111 towards an ear region. This light is called inspection lightbecause it interrogates the surface of the ear, penetrates the skin ofthe ear, and generates a scattered light response 110 which mayeffectively inspect blood vessels within the ear region. The opticaldetector 26 detects scattered light 110 from an ear region and thelight-guiding region 19 of the light guide 18 guides the light to theoptical detector 26 through the light-guiding region 19, as illustrated.

In the embodiment of FIG. 3, the light-guiding earbud 30 is configuredfor optical coupling that is parallel to the light guide (i.e., cover18). The optical detector 26 and optical emitter 24 are configured todetect and generate light substantially parallel to the light-guidingregion 19 of the light guide 18. For example, the light guide 18 definesan axial direction A₁. The optical emitter 24 and optical detector 26are each oriented such that their respective primary emitting anddetecting planes P₁, P₂ are each facing a respective direction A₃, A₂that is substantially parallel with direction A₁.

The light guiding region 19 of the light guide 18 in the illustratedembodiment of FIG. 3 is defined by cladding material 21 that helpsconfine light within the light guiding region 19. The cladding material21 may be reflective material in some embodiments. In other embodiments,the cladding material may be optically transparent or mostly transparentwith a lower index of refraction than the light transmissive material ofthe cover 18. The cladding 21 may be a layer of material applied to oneor more portions of the inner and/or outer surfaces 18 a, 18 b of thelight guide 18. In some embodiments, the outer surface 16 a of theearbud housing 16 may serve as cladding that confines light within thelight-guiding region 19. In some embodiments, the light transmissivematerial of the light guide 18 may be composed of a material having ahigher index of refraction than the cladding material 21. In someembodiments, air may serve as a cladding layer.

In the embodiment of FIG. 4A, the light-guiding earbud 30 is configuredfor optical coupling that is substantially perpendicular to the lightguide (i.e., cover 18). The optical detector 26 and optical emitter 24are configured to detect and generate light substantially perpendicularto the light-guiding region 19 of the light guide 18. For example, thelight guide 18 defines an axial direction A₁. The optical emitter 24 andoptical detector 26 are each oriented such that their respective primaryemitting and detecting planes P₁, P₂ are each facing a respectivedirection A₃, A₂ that is substantially perpendicular to direction A₁.The orientation of the optical emitter 24 and optical detector 26 inFIG. 4A may be convenient for manufacturing purposes, whereside-emitting LEDs and side-detecting photodetectors can couple directlyto the light-guiding region 19 for generating light 111 and detectinglight 110. This may relax size constraints for an earbud 30 because thedimensions of the light-guiding region 19 may be independent of theoptical emitter 24 and optical detector 26.

FIG. 4B illustrates the light-guiding earbud 30 of FIG. 4A modified suchthat the earbud cover 18 and cladding material 21 are elongated to reachdeeper within the ear canal C of a subject, and closer to the tympanicmembrane, for example. In the illustrated embodiment of FIG. 4B, thereare no apertures in the housing 16 or cover 18. Acoustic energy 44from/to the speaker/microphone passes through the material of the cover18 and housing 16. The illustrated elongated configuration serves asboth an optical light-guiding region and an acoustic wave-guidingregion.

FIG. 4C illustrates the light-guiding earbud 30 of FIG. 4A modified suchthat the earbud cover 18 and cladding material 21 are elongated to reachdeeper within the ear canal C of a subject, and closer to the tympanicmembrane, for example. In the illustrated embodiment of FIG. 4C,apertures 34 a, 34 b in the housing 16 and cover 18 are provided. Assuch, the optical light-guiding region 19 and the acoustic wave-guidingregion 54 are isolated from each other. The light-guiding region 19 maybe a light transmissive material, such as a dielectric material, and theacoustic wave-guiding region 54 may be air or another material, and theseparation between these regions may be defined by at least part of thecladding material 21. Embodiments of the present invention may includemultiple openings 34 a, 34 b in the housing 16 and cover 18. Theseparation between the light-guiding region 19 and the acousticwave-guiding region 54 may be defined by other structures composed of avariety of possible materials. Specific examples of these materialsinclude plastic molding, metals, polymeric structures, compositestructures, or the like.

FIG. 4D illustrates the light-guiding earbud 30 of FIG. 4A modified suchthat the earbud cover 18 and cladding material 21 are elongated to reachdeeper within the ear canal C of a subject, and closer to the tympanicmembrane, for example. In the illustrated embodiment of FIG. 4D, thearea within the housing 16 may be air, silicone, plastic, or anymaterial capable of passing sound. As such, at opening 34 b, aninterface exists between the material of the light-guiding region 19 andthe material within the housing 16. In some embodiments, thelight-guiding region 19 and the region within the housing 16 may both beair. In other embodiments, the light-guiding region 19 and the regionwithin the housing 16 may be formed from the same or differentmaterials. In some embodiments, the region within the housing 16 may beformed from an optical wave guiding material identical or similar to thematerial in the light-guiding region 19.

In the embodiments of FIGS. 4B-4D, the optical energy 110 coming fromthe ear may include optical wavelengths, such as IR wavelengths,emitting from the tympanic membrane due to black body radiation. If theoptical detector 26 is configured to measure this black body radiation,then the earbud can be used to measure tympanic temperature, bloodanalyte levels, neurological, electrical activity, or metabolic activityof the earbud wearer.

Referring to FIG. 5, a light-guiding earbud 30 is configured for opticalcoupling that is parallel to the light guide (i.e., cover 18) as in theembodiment of FIG. 3. However, the embodiment of FIG. 5 does not includea separate earbud housing. Instead, the light guide 18 serves thefunction of the earbud housing. In addition, the light guide 18 includesmultiple windows 18 w formed in the cladding material 21 on the outersurface 18 a of the cover and through which light 111 emitted by thelight emitter 24 passes and multiple windows 18 w through whichscattered light 110 passes into the light guide 18 to be directed to thelight detector 26. These openings 18 w may extend circumferentiallyaround the light guide 18 or may partially extend circumferentiallyaround portions of the light guide 18. In some embodiments of thisinvention, the earbud housing and light guide 18 may be separated, asshown in other figures.

In addition, the illustrated light guide 18 of FIG. 5 is surrounded by alayer 29 of light transmissive material. One or more lenses 29L areformed in this layer 29 and are in optical communication with respectivewindows 18 w in the light guide 18. In the illustrated embodiment, alens 29L is in optical communication with a respective window 18 wthrough which emitted light 111 passes, and a respective window 18 wthrough which scattered light 110 passes. Lenses 29L are configured tofocus inspection light 111 onto a particular region of the ear. Lenses29L are configured to help collect scattered light 110 and direct thescattered light 110 into the light guiding region 19. In someembodiments, these lenses 29L may be a molded part of the light guide18. The illustrated location of lenses 29L in FIG. 5 is non-limiting,and the lenses 29L may be located wherever optical coupling between theearbud and ear is desired. Though convex lens embodiments are shown inFIG. 5, this is not meant to limit embodiments of the present invention.Depending on the desired optical coupling and configuration of theearbud against the ear, a variety of lens types and shapes may beuseful, such as convex, positive or negative meniscus, planoconvex,planoconcave, biconvex, biconcave, converging, diverging, and the like.

Referring now to FIG. 6, a light guiding earbud 30, according to someembodiments of the present invention, includes a base 50, an earbudhousing 16 extending outwardly from the base 50 that is configured to bepositioned within an ear E of a subject, and a cover 18 of lighttransmissive material surrounding the earbud housing 16 that forms alight-guiding region 19. The earbud housing 16 is in acousticalcommunication with a speaker 22 and includes at least one aperture 34 athrough which sound from the speaker 22 can pass. The earbud housing 16encloses the speaker 22, an optical emitter 24 and an optical detector26 as illustrated. An additional light detector 26 is located on thebase 50 but is not surrounded by the earbud housing 16.

The earbud housing 16 is formed of a cladding material. The claddingmaterial may be reflective material in some embodiments. In otherembodiments, the cladding material may be optically transparent ormostly transparent with a lower index of refraction than the lighttransmissive material of the cover 18. In some embodiments, the earbudhousing 16 may be replaced by air, such that the cladding region is air.Air may have a smaller index of refraction than that of the cover 18,supporting light transmission along the cover 18. In other embodiments,a cladding region exists between the earbud housing 16 and thelight-guiding region 19. In another embodiment, a cladding region existscovering the outside of light-guiding region 19, with the exception ofregions surrounding the lens regions 18L.

A plurality of windows 16 w are formed in the earbud housing 16 atselected locations to permit light emitted by the light emitter 24 topass therethrough. In some embodiments, the earbud housing 16 may havetranslucent or transparent material that serves the function of one ormore windows 16 w. The cover 18 includes a plurality of lenses 18L thatare in optical communication with respective windows 16 w in the earbudhousing 16. These lenses 18L are configured to focus light 111 passingthrough a respective window 16 w towards a particular region of the earof a subject, and to help collect scattered light 110 and direct thescattered light 110 into the earbud housing 16 towards the lightdetector 26.

The earbud 30 of FIG. 6, via the locations of windows 16 w, producesisotropic optical coupling, such that the light generated by the opticalemitter 24 is roughly identical in all directions with respect to theearbud housing 16. The inspection light 111 generated by the opticalemitter 24 passes isotropically into the light guiding region 19 throughthe windows 16 w.

A benefit of light guiding earbud 30 of FIG. 6 is that manufacturing maynot require alignment of the light-guiding region 19 with respect to theoptical emitter 24 and detector 26. This may be in part because theoptical energy density generated/detected by the opticalemitter/detector may be the same, or relatively uniform, within theearbud housing 16 regardless of alignment of the light guide 18 withrespect to the earbud housing 16 or regardless of alignment between theoptical emitters/detectors and the earbud housing 16. This effect may besimilar to that observed in “integrating spheres” commonly used forquantifying the lumen output of an optical source. Namely, because thelight from the optical emitter 24 may be substantially isotropic and notfocused, there is less restriction on the alignment of the earbudhousing and earbud cover with respect to the optical emitter 24 oroptical detector 26.

Referring now to FIGS. 7A-7B, a light guiding earbud 30, according tosome embodiments of the present invention, includes a base 50, and anearbud housing 16 extending outwardly from the base 50 that isconfigured to be positioned within an ear E of a subject. The earbudhousing 16 is formed from translucent material such that light can passtherethrough and forms a light-guiding region 19. The earbud housing 16is in acoustical communication with a speaker 22 and includes at leastone aperture 34 a through which sound from the speaker 22 can pass. Apair of optical detectors 26 are secured to the base 50 but are notsurrounded by the earbud housing 16, as illustrated.

The earbud housing 16 includes a flexible optical emitter 24 integrallyformed within the housing 16, as illustrated. The optical emitter 24 isflexible such that it may be positioned around the earbud in an earbudform-factor. The flexible optical emitter 24 is configured to beconformable to an earbud shape and configuration. The flexible opticalemitter 24 may be in, near, or part of the earbud housing 16, claddingmaterial 21, or housing 16. In some embodiments, the flexible opticalemitter 24 may be part of a flexible optical circuit inserted into anearbud 30.

The optical detectors 26 positioned outside the earbud housing 16 of theearbud 30 of FIGS. 7A-7B collect scattered light from an ear originatingfrom inspection light 111 generated by the flexible optical emitter 24.The flexible optical emitter 24 may be mounted to the earbud base 50through one or more electrical connectors 24 a. In some embodiments,these may be soldered, wired, or detachable connectors. In someembodiments, the flexible optical emitter 24 may include a flexibleoptical detector. In some embodiments, the flexible optical emitter 24may be part of a flexible optical circuit comprising the form-factor of24 shown in FIGS. 7A-7B, where the flexible optical circuit may includeone or more optical emitters and detectors as well as amplifiers,microprocessors, wireless circuitry, and signal conditioningelectronics. In some embodiments, the flexible optical circuit mayinclude a complete chipset for physiological and environmental detectionand for wired/wireless transfer of data to a remote location. Forexample, these flexible devices may include an organic LED (OLED) and anorganic optical detector circuit. This embodiment may be useful forgenerating a diffuse light beam towards the ear region and for detectinga diffuse optical scatter response from the ear region. In someembodiments, the emitter and detector on the flexible optical emitter 24may be a traditional light-emitting diode (LED) and photodetector (PD)integrated onto a flexible printed circuit board. In other embodiments,transparent solid state optical emitters, detectors, or switches may beused. For example, an electrically controlled liquid crystal matrix maybe embedded within an earbud, covering the flexible optical emitter 24.This may allow localized control of light flow to selected areas from/tothe earbud going towards/away-from the ear. Additionally, this may allowlocalized control of light wavelength to selected areas.

Referring now to FIGS. 8A-8B, a light guiding earbud 30, according tosome embodiments of the present invention, includes a base 50, an earbudhousing 16 extending outwardly from the base 50 that is configured to bepositioned within an ear of a subject, and a cover 18 that surrounds theearbud housing 16. The earbud housing 16 is in acoustical communicationwith a speaker 22 and includes at least one aperture 34 a through whichsound from the speaker 22 can pass. The cover 18 includes at least oneaperture 34 b through which sound from the speaker 22 can pass. Thecover 18 includes a cladding material 21 on the outer surface 18 athereof, except at end portion 18 f, as illustrated. In the illustratedembodiment, there is no cladding material on the cover inner surface 18b. The housing 16 is in contact with the cover inner surface 18 b andserves as a cladding layer to define the light guiding region 19. Thecover 18 with the illustrated cladding material 18 c serves as a lightguide that delivers light from the optical emitters 24 into an ear canalof a subject through cover end portion 18 f. The cover 18 also collectslight through end portion 18 f and delivers the collected light to theoptical detectors 26. Various configurations and arrangements of opticalemitters and detectors may be utilized in accordance with embodiments ofthe present invention.

In the illustrated embodiment of FIGS. 8A-8B, to reduce the risk of theinspection light 111 interrogating and saturating the optical detectors26, a bottom portion 16 a of the earbud housing 16 includes a lightblocking region that blocks light from passing therethrough. This lightblocking region 16 a may be a black-painted region, an optically opaqueregion, or a material or structure that blocks light transmission. Theillustrated configuration of the earbud housing 16 and bottom portion 16a may help confine inspection light 111 generated by the opticalemitters 24 within the light-guiding layer (i.e., 19), guiding thislight towards the ear region through the end portion 18 f of the earbud30.

In some embodiments, as illustrated in FIG. 8C, the earbud housing 16may be at least partially reflective to scatter light within the cavitydefined by the earbud housing 16. In such case, the optical energy 111may exit the earbud 30 through apertures 34 a, 34 b in the housing 16and cover 18. An advantage of this configuration is that light 111 canbe focused on a particular region of the ear where a particularphysiological activity may be located. Also, this configuration mayreduce unwanted optical signals from regions that may not be relevant tothe physiological activity of interest. Although FIG. 8C shows theapertures 34 a, 34 b positioned toward the tympanic membrane, theapertures 34 a, 34 b may be located at one or more other locations aboutthe earbud 30. For example, an aperture may be formed in the housing 16and cover 18 at the location where the earbud 30 contacts the antitragusof an ear to allow optical energy 111 to interrogate the antitragusregion of the ear.

In some embodiments, as illustrated in FIG. 8D, the earbud housing 16may contain a material that reflects one or more wavelengths of lightand transmits one or more wavelengths of light. For example, the earbudhousing 16 may be comprised of a polymer, plastic, glass, compositematerial, or resin that reflects visible wavelengths and transmits IRwavelengths. Exemplary materials include color absorbing materials, suchas organic dyes, found in photographic film. Alternatively, the earbudhousing 16 may include an optical filter region, such as a Bragg filteror other optical filter layer deposited on one or more sides of thehousing region. If an optical detector 26′ is configured to measurevisible wavelengths only, then the optical energy detected by opticaldetector 26′ may consist primarily of optical energy scattered from theearbud housing 16, and the optical energy detected by the opticaldetectors 26 may consist of optical energy scattered from the earregion. This configuration may be useful because the signal from theoptical detector 26′ may represent motion noise which may be removedfrom the signal derived from the optical detectors 26, which may containphysiological information and motion noise.

Referring now to FIGS. 9A-9B, a light guiding earbud 30, according tosome embodiments of the present invention, includes a base 50, an earbudhousing 16 extending outwardly from the base 50 that is configured to bepositioned within an ear of a subject, and a cover 18 surrounding theearbud housing 16. The earbud housing 16 is in acoustical communicationwith a speaker 22 and includes at least one aperture 34 a through whichsound from the speaker 22 can pass. The cover 18 includes at least oneaperture 34 b through which sound from the speaker 22 can pass. A pairof optical emitters 24 are secured to the base 50 and are surrounded bythe earbud housing 16, as illustrated. An optical detector 26 is securedto the base 50 and is not surrounded by the earbud housing 16, asillustrated. The cover 18 serves as a light guide that delivers lightfrom the optical emitters 24 into an ear canal of a subject.

The light-guiding region 19 of the cover 18 is designed to diffuse lightand/or to generate luminescence. In this embodiment, the light-guidingregion 19 includes at least one optical scatter or luminescence region.The optical scatter or luminescence region may be located anywherewithin the earbud in the optical path of the optical emitters 24, butpreferably within or about the cladding layer itself. When inspectionlight 111 generated by the optical emitters 24 is scattered or by anoptical scatter region, this light may form a more diffuse optical beam111 a that is more uniform across the earbud 30 than the inspectionlight 111 generated by the optical emitters 24. This diffused beam,having an intensity distribution being less sensitive to motion of theear, may be useful in alleviating motion artifacts in the scatteredlight coming from the ear, such that the scattered light coming from theear, measured by the optical detector 26, is more indicative of bloodflow changes within blood vessels and less indicative of mouth movementsand body motion. The optical scatter region within the light-guidingregion 19 may be at least partially comprised of impurities ormorphological differences within the light-guiding region. An example ofsuch impurities may include point defects, volume defects, nativedefects, metallics, polymers, microspheres, phosphors, luminescentparticles, air pockets, particles, particulate matter, and the like. Anexample of morphological differences may include density variations,roughness, air pockets, stoichiometry variations, and the like. As aspecific example, the light-guiding region 19 may comprise a transparentmaterial, such as glass, a polymer, or silicone, and a luminescentimpurity, such as a phosphor or luminescent polymer or molecule, may beintegrated within the light-guiding region. This configuration maygenerate luminescence within the light-guiding region 19 in response tooptical excitation from the optical emitters 24. In other embodiments,nanoscale fluctuations or impurities may be used to diffuse ormanipulate light through the earbud. Examples of nanoscale fluctuationsor impurities may include quantum dots, rods, wires, doughnuts, or thelike.

FIG. 9C illustrates an exemplary homogeneous distribution of luminescentparticles 44, such as phosphors, embedded within the earbud cover 18,according to some embodiments of the present invention. FIGS. 9D-9Eillustrate an exemplary distribution of luminescent particles 44, suchas phosphors, where the particles are distributed near one or moresurfaces of the earbud cover 18, according to some embodiments of thepresent invention.

In another embodiment, an optical scatter or luminescent region may beat least partially located in a separate region from the light-guidingregion 19, such as a coating, that may be in physical contact with thelight-guiding region 19.

In another embodiment, the optical scatter region or luminescent regionmay include multiple layers of light-guiding material having at leastone dissimilar optical property, such as a dissimilar index ofrefraction, transparency, reflectivity, or the like. In anotherembodiment, the optical scatter region may include one or more patternedregions having at least one dissimilar optical property.

In another embodiment, the optical scatter or luminescent region may bedistributed at select locations throughout the earbud.

FIG. 10 illustrates relevant anatomy of a human ear E. Blood vessels arelocated across the ear, but it has been discovered thatphotoplethysmography (PPG) signals are the strongest near theantitragus, tragus, lobule, and portions of the acoustic meatus, and theear canal. The antitragus is a particularly attractive location forphotoplethysmography because a strong PPG signal can be derived withminimal motion artifacts associated with running and mouth motion.

Referring now to FIGS. 11A-11B, a light guiding earbud 30, according tosome embodiments of the present invention, includes a base 50, an earbudhousing 16 extending outwardly from the base 50 that is configured to bepositioned within an ear of a subject, and a cover 18 surrounding theearbud housing 16. The earbud housing 16 is in acoustical communicationwith a speaker 22 and includes at least one aperture 34 a through whichsound from the speaker 22 can pass. The cover 18 includes at least oneaperture 34 b through which sound from the speaker 22 can pass. Thecover 18 serves as a light guide for directing light into an ear of asubject and defines a light-guiding region 19. The illustrated earbud 30is configured to focus light towards the antitragus of the ear of ahuman. In the illustrated embodiment, there is no cladding material onthe outer surface 18 a or inner surface 18 b of the cover 18. Air servesas a cladding layer at the outer surface 18 a and the housing 16 servesas a cladding layer at the inner surface 18 b. Air may serve as asufficient cladding layer due to the index of refraction differencebetween air and the light guiding layer. Namely, the index of refractionof the light-guiding layer 19 may be more than that of air.

A sensor module 70 is located near the earbud periphery, as illustrated.This sensor module 70 is shown in more detail in FIGS. 12 a-12B, and isdescribed below. Three benefits of locating the sensor module 70 nearthe periphery of the light-guiding earbud 30 are: 1) PPG signals nearthe antitragus are less corrupted by motion artifacts than are PPGsignals in other blood-vessel-rich regions of the ear; 2) the sensormodule 70 may be designed somewhat independently of the earbud 30,liberating earbud comfort maximization from PPG signal maximization; and3) because design constraints may be liberated, sensors need not belocated in the acoustic cavity (i.e., within the earbud housing 16),allowing sound to pass through the acoustic orifices 34 a, 34 b withminimal interference. In this embodiment, it may be beneficial toincorporate lenses within the cover 18, similar to the lenses 18L ofFIG. 6. It may be beneficial to extend the light-guiding region 19 ofthe cover 18 near the location where the earbud 30 rests near theantitragus. This light-guide extension 19 a serves as an additionallight-coupling region and may improve optical coupling from thelight-guiding region 19 to an ear region and/or improve optical couplingfrom an ear region to the light-guiding region 19, including theantitragus and portions of the acoustic meatus. This is because thisextended light-guiding region 19 a may provide skin contact between thelight guiding layer 19 and the skin, providing better optomechanicalstability and optical coupling. In this embodiment, light may coupleinto the extended light-guiding region 19 a, from an optical emitter 24,and into the ear region. Similarly, light may couple from the earregion, into the extended light-guiding region 19 a, and to the opticaldetector 26. This extended light-guiding region 19 a may appear as abulb or lens near the bottom of the earbud cover 18.

FIGS. 12A-12B illustrate respective opposite sides of a sensor module 70that may be located near the periphery of an earbud 30, for example asillustrated in FIGS. 11A-11B, according to some embodiments of thepresent invention. Sensor module 70 may include a number of electroniccomponents capable of converting various forms of energy into anelectrical signal and digitizing the signal. For example, the sensormodule 70 may include light-emitting diodes, optical sensors,accelerometers, capacitive sensors, inertial sensors, mechanicalsensors, electromagnetic sensors, thermal sensors, nuclear radiationsensors, biological sensors, and the like. In some embodiments, theoptical emitters of this invention may be a combination ofside-emitting, edge-emitting, or surface-emitting light-emitting diodes(LEDs) or laser diodes (LDs).

In the illustrated embodiment of FIGS. 12A-12B, the sensor module 70includes two sets of optical emitters 24 a, 24 b. The first set ofoptical emitters 24 a may be side-emitters (or edge-emitters) that arelocated at the top of the module 70 and direct light towards the earbudtip (e.g., cover end portion 18 f, FIG. 8A) and towards the acousticmeatus and/or ear canal of the ear. The second set of optical emitters24 b may be located near the middle of the module 70 and may directlight in a beam that is largely perpendicular to that of theside-emitters 24 a. In this particular embodiment, a single opticalemitter 24 b is shown mounted on a circuit board 70 c such that thisoptical emitter 24 b directs light towards the antitragus, which islocated largely perpendicular to the acoustic meatus.

The optical energy generated by these optical emitters 24 a, 24 b may bescattered by blood vessels in the ear. This scattered light may be atleast partially captured by the optical detectors 26. This light may bedigitized by an optical detector 26 itself or with other circuitry onthe sensor module circuit board 70 c. The light-guiding design of theaforementioned light-guiding earbuds 30 may direct light towards each ofthese detectors 26. For example, this may be accomplished via thelight-guiding earbud 30, wherein a lens (e.g., 18L, FIG. 6) facilitatesinspection light coupling from the optical emitters 24 into the earregion and facilitates scattered light coupling to the optical detectors26 from the ear region. Additional sensor components 27 a, 27 b may beused to measure an orthogonal energy component, facilitate sensoranalysis, and thus help generate physiological assessments. For example,sensor components 27 a, 27 b may be thermal sensors for measuring thetemperature of the inner ear (using the thermal sensors 27 a facing theear region) with respect to the outer ear (using the thermal sensor 27 bfacing away from the ear region). By subtracting the two measureddigitized temperatures from these two sensors 27 a, 27 b, an indicationof heat flow from the ear can be generated. This temperaturedifferential may be mathematically related to metabolic rate. Forexample, this temperature differential may be directly proportionalmetabolic rate. These temperature sensors may include thermistors,thermopiles, thermocouples, solid state sensors, or the like. They maybe designed to measure thermal conduction, convection, radiation, or acombination of these temperature components.

The earbud-facing side (FIG. 12B) of the sensor module 70 may includesensors that do not need to be located on the antitragus-facing side ofthe sensor module. For example, one or more inertial sensors 27 c may belocated on the earbud-facing side (FIG. 12B) of the sensor module 70. Ina particular embodiment, the inertial sensor 27 c may be a 3-axisaccelerometer, and because this sensor does not need to optically couplewith the ear region, a better use of sensor real estate may be to locatethis sensor on the earbud-facing side of the sensor module 70.Additional optical emitters 24 a, 24 b may be located on theearbud-facing side to facilitate an optical noise reference. Namely, asthe person wearing the earbud module 30 moves around, the interrogationlight generated by the optical emitters 24 a, 24 b may be scattered offthe earbud and be detected by optical detectors 27 d. This scatteredlight intensity, phase, and/or frequency due to body motion may beproportional to the motion-related component of the scattered lightintensity from the ear region. The motion-related component is thecomponent due to the physical motion of the ear and not the componentrelated to blood flow. Thus, the optical scatter signal collected by thedetectors 27 d may provide a suitable noise reference for an adaptivefilter to remove motion artifacts from the scattered light from the earregion, generating an output signal that is primarily related to bloodflow (which may be the desired signal). In the same token, the scatteredlight reaching the optical detectors 27 d may be used to generate ameasure of activity. The intensity, phase, and frequency of thisscattered light may be related to physical activity. Sinusoidalvariations of the heart rate waveform may be counted digitally, byidentifying and counting crests and peaks in the waveform, to generatean effective step count. Embodiments of the present invention, however,are not limited to the illustrated location of components in the sensormodule 70. Various types and orientations of components may be utilizedwithout limitation.

FIG. 19 illustrates the optical interaction between the sensor module 70of FIGS. 12A-12B and the skin of a subject. The sensor module 70 isshown in a reflective pulse oximetry setup 80 where reflectedwavelengths 110 are measured, as opposed to measuring transmittedwavelengths. The optical emitter and optical detector wavelengths forpulse oximetry and photoplethysmography may include ultraviolet,visible, and infrared wavelengths. In the illustrated embodiment, anoptical source-detector assembly 71 is integrated into sensor module 70to generate optical wavelengths 111 and monitor the resulting scatteredoptical energy 110. The optical source-detector assembly 71 contains oneor more optical sources emitting one or more optical wavelengths, aswell as one or more optical detectors detecting one or more opticalwavelengths.

The epidermis 90, dermis 91, and subcutaneous 92 layers of skin tissueare shown in FIG. 19 for reference. The scattered optical energy 110 maybe modulated in intensity by changes in blood flow in the blood vessels,changes in physical motion of the body, respiration, heart rate, andother physiological changes. In some cases, the scattered optical energymay be luminescent energy from the skin, blood, blood analytes, drugs,or other materials in the body.

As previously described, the optical scatter signal collected by thedetectors 27 d may provide a suitable noise reference for an adaptivefilter to remove motion artifacts from the scattered light from the earregion, generating an output signal that is primarily related to bloodflow (which may be the desired signal). This is because light detectedby these detectors would come from light that has not been scattered bya physiological region but rather light that has been scattered from aregion of the associated earpiece that may move along with the ear.Thus, the scattered light reaching the optical detectors 27 d may beused to generate a measure of activity.

FIG. 13 illustrates the basic configuration of an adaptive noisecancellation scheme 200 for extracting a physiological signal fromnoise. The two types of sensor inputs are represented by the terms“Channel A” and “Channel B”. Channel A refers to inputs from sensorsthat collect physiological information plus noise information, andChannel B refers to inputs from sensors that collect primarily (orsubstantially) noise information. Channel B information is passedthrough an electronic filter 203 whose properties are updated adaptivelyand dynamically. The filter 203 properties are updated to minimize thedifference between Channel A and the post-processed Channel B, denotedas B^. In this way, noise is removed from Channel A and Channel Ccontains predominantly physiological information from which parameterssuch as blood flow, heart rate, blood analyte levels, breathing rate orvolume, blood oxygen levels, and the like may be calculated. It isimportant to note that the Channel A information can still be usefuldespite the presence of noise, and the noise information may still beutilized for the computation of relevant parameters. For instance, theresidual noise information in Channel A may be extracted by a parameterestimator 201 and the output in Channel D may be one or more activityassessments or the like. Similarly, the raw noise channel, Channel B,may be post-processed by a parameter estimator 205 to extract activityassessments for Channel E. Activity assessments may include exertion,activity level, distance traveled, speed, step count, pace, limb motion,poise, performance of an activity, mastication rate, intensity, orvolume, and the like. The noise cancellation scheme 200 may beintegrated into the firmware of a microprocessor or the like.

Although the embodiment of FIG. 13 for cancelling motion noise has beenpresented for an earbud configuration, this does not limit the inventionto earbuds. An element of the adaptive noise cancellation scheme 200 forcancelling motion noise with an optical noise source may be that theoptical detectors (such as 27 d) are configured such that they do notreceive scattered light from a physiological region while the detectorsare simultaneously receiving scattered light from a region that ismoving in synchronization with the physiological region. Even theslightest physiological signal existing in the optical noise referenceof Channel B may prevent the adaptive filter from working properly suchthat the physiological signal may inadvertently be removed altogether bythe filter 203. Furthermore, although the noise source Channel B isdescribed as an optical noise source, other forms of energy may be usedin this invention. Namely, any inertial sensor input may constitute theinput for Channel B. More specifically, a sensor for measuring changesin capacitance along the earbud with respect to the ear may provide aninertial noise reference without also measuring physiologicalinformation. Similarly, an accelerometer may provide an inertial noisereference without also measuring physiological information. An inductivesensor may also provide an inertial noise reference without alsomeasuring physiological information. For each noise source, a definingelement may be that the noise source may be configured to measurephysical motion only (or mostly) and not physiological information (suchas blood flow, blood oxygen, blood pressure, and the like). The utilityof an optical noise source is that because the optical signal Channel Aand the optical noise Channel B have the same linearity response, theadaptive filter scheme 200 may be more effective than the case where thesignal and noise channels operate via different forms of sensed energy.For example, the response linearity characteristics of an accelerometersensor in response to inertial changes may not be the same as theresponse linearity characteristics of an optical sensor.

The adaptive noise cancellation scheme 200 for cancelling motion noisewith an optical source (specifically an infrared LED) has beendemonstrated in the laboratory, with a human wearing a light-guidingearbud while resting, jogging, and running over a treadmill, and variousdata summaries 300 a-300 d are presented in FIGS. 14A-14D. The data wasrecorded by a chip and memory card embedded in an earbud 30, havingelectrical connectivity with the sensor module 70 within the earbud 30.The raw signal in low motion 300 a and raw signal in high motion 300 cmay be equated with the signal of Channel A of FIG. 13. Similarly, the“blocked channel” in low motion 300 b and “blocked channel” in highmotion 300 d may be equated with Channel B of FIG. 13. In thisexperiment, the “block channel” consisted of an optical noise source,wherein the optical noise source included an optical emitter-detectormodule such as 70 of FIGS. 12A-12B. However, instead of being exposed tothe ear, the optical emitter-detector module was covered with a layer ofclear silicone that was then covered by black tape to prevent light fromthe emitter (such as 24 a and 24 b) from reaching the ear. Thus, scatterfrom the black tape was scattered back to the emitter-detector modulethrough the silicone and sensed as motion noise by the detectors (suchas 26 and 27 d). In a sense, for this configuration, the optical channelto the human ear is “blocked”, hence the term “blocked channel”. Thepurpose of the clear silicone below the black tape was to: 1) provide anunobstructed, transparent optical scatter path for the IR light and 2)provide motion sensitivity similar to that of human skin, as siliconehas a vibration response that may be similar to that of human skin.

FIGS. 14A-14D show that the raw signal in low motion 300 a indicatesblood flow pulses which can be translated as heart rate. This is becauseeach blood flow pulse represents one heart beat. However, the raw signalin high motion 300 c indicates measured mostly physical activity. Thisis evident by the fact that the high motion signal 300 c matches thecorresponding blocked channel signal 300 d, and the blocked channel inhigh motion 300 d was found to have a substantially identical beatprofile with the measured steps/second of the runner.

FIG. 15 is a graph of processed physiological signal data from a headsethaving one or more light-guiding earbuds 30, according to someembodiments of the present invention. Specifically, FIG. 15 shows theanalysis results 400 of the data summaries 300 a-300 d presented inFIGS. 14A-14D of blood flow (y-axis) versus time (x-axis) following twodata processing sequences to extract heart rate. One sequenceincorporated the adaptive filtering process 200 of FIG. 13 as well as abeat finder processing step. The second sequence incorporated the beatfinder processing step without the adaptive filtering process 200 ofFIG. 13. The beat finder process counts each heart beat by monitoringthe peaks and valleys of each pulse, such as the peaks and valleys shownin the graph 300 a of FIG. 14A. As shown in FIG. 15, the beat finder waseffective at measuring heart rate during resting and jogging. However,the beat finder alone was not sufficient for monitoring heart rateduring running. This is because at high motion, the signal 300 d (FIG.14D) associated with footsteps is strong enough to overwhelm the smallersignal associated with heart rate, and so the motion-relatedcontribution dominated the overall signal 300 d. Thus, the beat findercannot distinguish heart beats from footsteps. By employing the adaptivefiltering process 200 (FIG. 13) before the beat finder process, thefootstep motion artifacts during running were effectively removed fromthe sensor signal (Channel A of FIG. 13) such that the output signal(Channel C of FIG. 13) contained blood flow information with minimalmotion artifacts. Thus, this output signal contained blood flow pulsesignals that could then be “counted” by the beat finder to generate anaccurate heart rate assessment.

In the specific analysis results 400 of FIG. 15, a beat finder wasemployed, following the adaptive filter process 200 of FIG. 13, to countheart beats. A more general method 500 for extracting physiologicalinformation from sensor signals in the midst of noise is illustrated inFIG. 16. The first block (block 510) represents the pre-adaptive signalconditioning stage. This process may utilize a combination of filters toremove frequency bands outside the range of interest. For example, acombination of band-pass, low-pass, and/or high-pass filters (such asdigital filters) may be used. The second block (block 520) represents anadaptive filtering process such as the process 200 described in FIG. 13.This process may utilize the pre-conditioned signals from block 510 asinputs into an adaptive filter that reduces motion or environmentalartifacts and noise in the primary data channel. The third block (block530) represents the parameter extraction stage. This process may utilizea combination of signal conditioning filters in addition to peak finding(such as beat finding) algorithms to calculate properties of interest(e.g. heart rate, blood flow, heart rate variability, respiration rate,blood gas/analyte level, and the like). The method 500 of FIG. 16 may beencoded in the firmware of a microprocessor (or similar electronics) tofacilitate real-time processing of physiological information.

FIG. 17 is a block diagram that illustrates sensor signals beingprocessed into a digital data string including activity data andphysiological data using the method 500 of FIG. 16, according to someembodiments of the present invention. Optical detectors 26 and opticalemitters 24 may include digitizing circuitry such that they may beconnected serially to a digital bus 600. Data from the detectors 26 maybe processed by a processor/multiplexer 602 to generate multiple dataoutputs 604 in a serial format at the output 606 of the processor 602.In some embodiments, the processing methods may involve one or more ofthe methods described in FIGS. 13, 14A-14D, 15 and 16. The multiple dataoutputs 604 may be generated by the processor/multiplexer 602 by timedivision multiplexing or the like. The processor 602 may execute one ormore serial processing methods, wherein the outputs of a plurality ofprocessing steps may provide information that is fed into themultiplexed data outputs 604.

The multiplexed data outputs 604 may be a serial data string of activityand physiological information 700 (FIG. 18) parsed out specifically suchthat an application-specific interface (API) can utilize the data asrequired for a particular application. The applications may use thisdata to generate high-level assessments, such as overall fitness oroverall health. Furthermore, the individual data elements of the datastring can be used to facilitate better assessments of other individualdata elements of the data string. As a specific example, the Blood Flowdata string may contain information on the first and second derivativesof each blood pulse. This information may be processed from a PPG signalby running the adaptively filtered heart rate signal through aslope-finder algorithm (such as a differentiator circuit). In anotherexample, the filtered PPG signal may be run through an integrationcircuit to estimate blood volume over each blood pulse. This informationmay then be used to assess blood pressure and blood oxygen levels moreaccurately than a direct measurement of blood pressure or blood oxygenlevels.

In some embodiments of the invention, new methods of generatingphysiological assessment algorithms are enabled. These new methods maybe achieved by measuring each data output of the data output string 604in real time while an earbud user is also wearing one or more benchmarksensors. Principal component analysis, multiple linear regression, orother statistical or machine learning techniques can then be used togenerate statistical relationships between the data outputs 604 and highlevel assessments measured simultaneously by the benchmark sensors.These benchmark sensors may measure aerobic fitness level, VO₂max, bloodpressure, blood analyte levels, and the like. The relationships betweenthe earbud sensor and benchmark sensor readings may be translated asalgorithms embedded in the earbud, wherein each algorithm generates atleast one assessment for the earbud user. In some cases, Bland-Altmanplots of the earbud-derived assessment value versus the benchmark valuemay be used to judge the effectiveness of the algorithm, and thisinformation may then feedback into improving the said earbud-derivedassessment algorithm. Examples of these assessments may include aerobicfitness level, VO₂max, blood pressure, blood analyte levels (such asblood glucose, oxygen, carbon monoxide, etc.), and the like.

In some cases, it may be important to remove the effects of ambientoptical noise from the physiological signal of a light-guiding earbud30. In such cases, one or more optical detectors 26 may be configured tomeasure outdoor or ambient lighting, and this information may be fedback into the processor 602 (FIG. 17) to extract external optical noisefrom the physiological signal. For example, some optical detectors maybe configured to measure light from the ear, whereas others may beconfigured to measure light from the ambient environment, such assunlight, room light, headlights, or the like. This may be achieved bydirecting the optical detectors towards and away from the ear,respectively. In a specific example, the ambient light reaching theoptical detectors 26 may generate an undesirable sinusoidal response onan optical detector that is configured to measure light from the ear.This undesirable sinusoidal noise response may be generated as an earbuduser moves their head from side to side while running. Thus, Channel Aof the adaptive filter 200 (FIG. 13) may include physiologicalinformation plus undesired ambient optical noise information. To removethis noise from the final output Channel C, the output of the opticaldetector configured to measure ambient optical noise may be an input(Channel B of FIG. 13) into the adaptive filter 200. In this way,ambient noise from Channel A may be removed to generate a mostlyphysiological signal in Channel C.

The optical detectors 26 and emitters 24 may be of multiple wavelengths,with the goal of providing specialized physiological information foreach wavelength. Referring to FIG. 19, for example, violet or UV lightmay be used to measure motion-related aspects of the ear, as violet andUV light may not penetrate greatly through the skin of the ear. Green,red, and IR wavelengths may have deeper penetration and provideinformation on the blood vessels and blood analyte levels. Bluewavelengths may be particularly useful for gauging changes in the sizeof the blood vessels.

Embodiments of the present invention may be more generally applied tonon-optical or mix-optical configurations. For example, one or more ofthe detectors 26 and emitters 24 may be mechanical, acoustical,electrical, gravimetric, or nuclear detectors and emitters, allproviding physiological information to the processor 602 (FIG. 17). Forexample, an accelerometer or capacitor may be used as a detector 26 forthe noise reference (Channel B) input of an adaptive filter running inreal-time on the processor 602.

Referring to FIG. 20, a chipset 800 for use in light-guiding earbuds 30,according to some embodiments of the present invention, may includeoptical emitters, optical detectors, mechanical, acoustical, electrical,gravimetric, nuclear detectors, additional sensors, signal processing,power regulation, digital control, and input/output lines. The chipset800 may include firmware for signal extraction and for generatingphysiological assessments from information derived from the sensors andnoise sources. One benefit of the chipset configuration is that thechipset 800 may be fully or partially integrated and hence compact andscalable to a wide range of products. To be integrated with alight-guiding earbud 30, the chipset 800 may be aligned such that thesensor region has an exposed window to a subject's ear. For example, thechipset 800 may be attached to the earbud base 50 or an earbud sensormodule 70 and aligned line-of-sight through an acoustic orifice of anearbud and/or through a transparent end portion of an earbud 30 (e.g.,through end portion 18 f of the earbud 30 of FIG. 8A-8B or 18 w of FIGS.4 & 5).

A specific embodiment of a chipset 800 for a stereo headset, accordingto some embodiments of the present invention, is illustrated in FIG. 21.This stereo chipset 800 may be integrated into an electronic module thatmay be attached to a printed circuit board. In another configuration,this stereo chipset 800 may be integrated into 3 modules, wherein theright and left earbud sensors comprise two separate modules, embedded inright and left earbuds respectively, and wherein the remaining circuitelements comprise the main module.

According to other embodiments of the present invention, monitoringdevices with light-guiding regions may be configured to be attached toearlobes, fingers, toes, other digits, etc. For example, FIGS. 22A-22Billustrate a monitoring device 70 that is configured to fit over afinger F, for example, as a finger ring, according to some embodimentsof the present invention. The illustrated monitoring device 70 includesa generally circular band capable of encircling a finger F of a subject,with a cylindrical outer body portion 72 and a generally cylindricalinner body portion 74 secured together in concentric relationship. Theouter body portion may be formed from virtually any type of material andmay have an ornamental configuration. In some embodiments, the outerbody portion 72 may include a flex circuit containing various electroniccomponents, such as a microprocessor, D/A converter, power source, powerregulator, and the like. However, in some embodiments, the outer bodyportion 72 may not be required and the circular band of the monitoringdevice 70 includes only the inner body portion 74 secured to the base 50(described below).

A base 50 is secured to the inner and outer body portions 74, 72 of theillustrated embodiment and may be similar to the base 50 described abovewith respect to FIGS. 3, 4A-4D, 5, 6, 7A-7B, 8A-8D, 9A-9B, and 11A-11B.The base 50 provides support for one or more sensors. In the illustratedembodiment, the base 50 supports an optical emitter 24, an opticaldetector 26, and an optical noise detector 26′.

The inner body portion 74 includes light transmissive material similarto that of the cover 18 described above with respect to FIGS. 3, 4A-4D,5, 6, 7A-7B, 8A-8D, 9A-9B, and 11A-11B. In some embodiments, the innerbody portion 74 is formed from a soft, resilient material, such assilicone, which deforms when a finger of a subject is insertedtherethrough. However, various types of light transmissive materials maybe utilized, without limitation.

A layer of cladding material 21 is applied to (or near) the outersurface 74 a of the inner body portion 74 and a layer of claddingmaterial 21 is applied to (or near) the inner surface 74 b of the innerbody portion 74, as illustrated, to define a light-guiding region 19. Assuch, the inner body portion 74 serves as a light guide that deliverslight from the optical emitter 24 to the finger F of a subject at one ormore predetermined locations and that collects light from the finger Fand delivers the collected light to the optical detectors 26, 26′. Insome embodiments, the cladding material 21 may be embedded within theinner body portion 74 adjacent to the outer surface 74 a and innersurface 74 b. In some embodiments, the outer body portion 72 may serveas a cladding layer adjacent to the inner body portion outer surface 74a.

In the illustrated embodiment, windows 74 w are formed in the claddingmaterial 21 and serve as light-guiding interfaces to the finger F. Theremay be any number of these windows, as may be required for sufficientoptical coupling, and the windows 74 w may include lenses such as thosedescribed above (e.g., lens 18L illustrated in FIG. 6), to focus lightemitted by the optical emitter 24 onto one or more portions of a fingerF and/or to focus collected light on the light detectors 26, 26′.Similarly, the windows 74 w may include optical filters to selectivelypass one or more optical wavelengths and reflect and/or absorb otheroptical wavelengths.

In the illustrated embodiment, the light-guiding region 19 includeslight blocking members 80 that isolate light emitter 24 and lightdetector 26 from each other. In some embodiments, only a single lightblocking member 80 may be utilized. For example, a single light blockingmember 80 may be positioned between the light emitter 24 and lightdetector 26. By adding an additional blocking member 80, as illustrated,the only light reaching the optical detector 26 may be light passingthrough at least one portion of the finger.

In some embodiments, multiple light emitters 24 may be utilized. Forexample, light emitters of different wavelengths may be utilized. Insome embodiments, multiple light detectors may be utilized that areconfigured to measure light at different wavelengths (e.g., lightdetectors 26 and 26′ may be configured to measure light at differentwavelengths). In this way, either optical detector may be configured tomeasure light mostly due to motion (such as finger motion) or to measurelight mostly due to physiological processes and motion. For example, ifthe windows 74 w incorporate IR-pass filters, visible light will notpass through the windows 74 w and the light will be scattered to thephotodetectors 26 and 26′. Or, if the two illustrated blocking regions80 are in place, and if photodetector 26′ is configured to measure onlyvisible light and photodetector 26 is configured to measure only IRlight, then only the photodetector 26′ will detect scattered visiblelight. As this visible scattered light cannot reach the finger, thescatter intensity measured by optical detector 26′ may be indicative ofmotion and not physiological activity.

Referring now to FIG. 23, a monitoring device 70′, according to someembodiments of the present invention, may be configured to be attachedto a body of a subject as a bandage or “band-aid”. The illustratedmonitoring device 70′ includes an outer layer or body portion 72 and aninner layer or body portion 74 secured together, as illustrated. Theouter body portion may be formed from virtually any type of material andmay have an ornamental configuration. In some embodiments, the outerbody portion 72 may include a flex circuit containing various electroniccomponents, such as a microprocessor, D/A converter, power source, powerregulator, and the like. However, in some embodiments, the outer bodyportion 72 may not be required and the monitoring device 70′ includesonly the inner body portion 74 secured to the base 50 (described below).

A base 50 is secured to the inner and outer body portions 74, 72 and maybe similar to the base 50 described above with respect to FIGS. 3,4A-4D, 5, 6, 7A-7B, 8A-8D, 9A-9B, and 11A-11B. The base 50 providessupport for one or more sensors. In the illustrated embodiment, the base50 supports an optical emitter 24, an optical detector 26, and anoptical noise detector 26′.

The inner body portion 74 is formed of light transmissive materialsimilar to that of the cover 18 described above with respect to FIGS. 3,4A-4D, 5, 6, 7A-7B, 8A-8D, 9A-9B, and 11A-11B. In some embodiments, theinner body portion 74 is formed from a soft, resilient material, such assilicone, which deforms when the device is attached to the body of asubject. However, various types of light transmissive materials may beutilized, without limitation.

A layer of cladding material 21 is applied to (or near) the outersurface 74 a of the inner body portion 74 and a layer of claddingmaterial 21 is applied to (or near) the inner surface 74 b of the innerbody portion 74, as illustrated, to define a light-guiding region 19. Assuch, the inner body portion 74 serves as a light guide that deliverslight from the optical emitter 24 to the body of a subject at one ormore predetermined locations and that collects light from the body anddelivers the collected light to the optical detectors 26, 26′. In someembodiments, the cladding material 21 may be embedded within the innerbody portion 74 adjacent to the outer surface 74 a and inner surface 74b. In some embodiments, the outer body portion 72 may serve as acladding layer adjacent to the inner body portion outer surface 74 a.

In the illustrated embodiment, windows 74 w are formed in the claddingmaterial 21 and serve as light-guiding interfaces to the body of asubject. There may be any number of these windows, as may be requiredfor sufficient optical coupling, and the windows 74 w may include lensessuch as those described above (e.g., lens 18L illustrated in FIG. 6), tofocus light emitted by the optical emitter 24 onto one or more portionsof the body of a subject and/or to focus collected light on the lightdetectors 26, 26′. Similarly, the windows 74 w may include opticalfilters to selectively pass one or more optical wavelengths and reflectand/or absorb other optical wavelengths.

In the illustrated embodiment, the light-guiding region 19 includes alight blocking member 80 that isolates light emitter 24 and lightdetector 26 from each other. In some embodiments, multiple lightemitters 24 may be utilized. For example, light emitters of differentwavelengths may be utilized. In some embodiments, multiple lightdetectors may be utilized that are configured to measure light atdifferent wavelengths (e.g., light detectors 26 and 26′ may beconfigured to measure light at different wavelengths).

The illustrated monitoring device 70′ may be removably attached to thebody of a subject via adhesive on one or more portions of the device70′. In some embodiments, adhesive may be on the inner body portion 74.In embodiments where the outer body portion is utilized, the adhesivemay be on the outer body portion 74. In some embodiments, theillustrated device 70′ may be removably attached to the body of asubject via tape or other known devices.

Referring now to FIGS. 24A-24B, 25A-25B, and 34-40, headsets 10 thatutilize one or more light guides 119 that are optically coupled with(i.e., in optical communication with) one or more optical emittersand/or optical detectors, according to various embodiments of thepresent invention, are illustrated. Each illustrated headset 10 includesa housing 14 that is configured to be supported within an ear of aperson, and may also enclose and protect various electronic componentsmounted to a base 50 (FIGS. 26-29) therewithin, as described above. Forexample, as described above, a base 50 may include any configuration andcombination of one or more printed circuit boards, electricalconnectors, processors, speakers, optical emitters and opticaldetectors. As such, each of the illustrated headsets 10 of FIGS.24A-24B, 25A-25B and 34-40 may include at least one optical emitter 24and at least one optical detector 26 disposed within the housing 14.However, as described below, one or more optical emitters and/or one ormore optical detectors may be remotely located from the housing 14. Asdescribed above, each optical detector 26 may be a photodiode,photodetector, phototransistor, thyristor, solid state device, opticalchipset, or the like. The optical emitter 24 may be a light-emittingdiode (LED), laser diode (LD), compact incandescent bulb, micro-plasmaemitter, IR blackbody source, or the like.

In the embodiments of FIGS. 24A-24B and 25A-25B, the distal end portion119 a of each of the light guides 119 extends outwardly from the housing14. However, in other embodiments of the present invention, the distalend portion 119 a of one or both light guides 119 may be substantiallyflush with the housing 14 or may even be recessed within the housing 14.The distal end 119 a of each light guide 119 has an exposed end surface119 c that is configured to engage (or be positioned adjacent) a portionof an ear of a subject.

The exposed surface 119 c is shown with a flat surface in FIGS. 24A-24Band as a curve or rounded surface in FIG. 31 to demonstrate that lightguides according to embodiments of the present invention may be shapedin a variety of ways to couple light to and from the body. For example,a rounded surface may improve light collection from a wider angle and aflat surface may narrow the field of view of the light guide. In somecases, a wider field of view may be important to measure more light froma broader range along the body, but in other cases, a narrower view maybe important to focus the field of view on a specific region of thebody. For example, a light guide 119 with a flat-faced surface 119 cwithin the earbud 10 of FIGS. 24A-24B may focus the field of view to theregion between the anti-tragus and concha of the ear. This region of theear has been found by Applicants to contain a sufficient blood flowsignal for photoplethysmography (PPG) while also being a region that isless prone to motion artifacts from chewing, talking, walking, running,or exercising. Less motion artifacts may result in less optical scatterfrom motion and hence result in less noise in the optical signal fromthe detector 26. A less noisy optical signal may result in a cleaner PPGsignal upon analog or digital filtering of the optical signal. Incontrast, a rounded distal end of a light guide as with the surface 119c of FIG. 31 may capture a greater PPG signal but an even greater amountof motion artifact related optical scatter. Detailed novel methods offiltering optical signals from the optical detector 26 are disclosed inco-owned, co-pending U.S. Patent Application Publication No.2012/0197093, and co-owned, co-pending PCT Application No.PCT/US12/48079, which are incorporated herein by reference in theirentireties.

As used herein, the term “engage” is intended to mean that the distalend surface 119 c may contact the skin of a person or may be closelyadjacent the skin of a person, such as within a hundred microns to 3 ormore millimeters away from the person, for example.

An opposite proximal end 119 b of each light guide 119 is in opticalcommunication with a respective optical emitter 24 and optical detector26. As such, a respective light guide 119 is configured to deliver lightfrom an optical emitter 24 into an ear region of the subject via thedistal end exposed surface 119 c, and a respective light guide 119 isconfigured to collect light from an ear region of the subject via thedistal end exposed surface 119 c and deliver collected light to theoptical detector 26.

In the illustrated embodiment of FIG. 34, the distal ends 119 a of eachlight guide 119 do not extend from the housing 14. Instead, the distalends 119 a of each light guide 119 are substantially flush with thehousing 14. In some embodiments, one or both of the distal ends 119 a ofthe light guides 119 of FIG. 34 may be recessed within the housing 14. Abenefit of recessing the light guides may be to further narrow the fieldof view or to improve the comfort of the headset 10 worn within the ear,as may be desired for some applications.

In the illustrated embodiment of FIGS. 24A-24B, the light guides 119have an elongated, generally cylindrical configuration. In theillustrated embodiment of FIGS. 25A-25B, the light guides 119 have anon-cylindrical, generally tapered configuration. In the embodiment ofFIG. 34, the light guides 119 have a generally oval cross-sectionalconfiguration. However, embodiments of the present invention are notlimited to the illustrated configuration or shape of the light guides119 of FIGS. 24A-24B, 25A-25B and 34-40. Light guides 119 according toembodiments of the present invention may have various shapes,configurations, lengths, etc., without limitation. A benefit of anon-cylindrical or square light guide is that it may facilitate a morecompact headset design.

Each light guide 119 in the various embodiments illustrated anddescribed herein may be formed from various types of light transmissivematerial, typically with a refractive index of at least one (1). In someembodiments, a light guide 119 may be formed from an elastomeric lighttransmissive material. In other embodiments, a light guide 119 may beformed from a substantially rigid light transmissive material. Inembodiments of the present invention where a headset or monitoringdevice includes a plurality of light guides 119, some of the lightguides may be formed from an elastomeric light transmissive material,and some may be formed from a substantially rigid light transmissivematerial. Light guides according to some embodiments of the presentinvention may comprise one or more optical fibers. Exemplary light guidematerials include, but are not limited to, polycarbonate, acrylic,silicone, and polyurethane.

Light guides 119, according to some embodiments of the presentinvention, may comprise optical filtering material, also. For example, alight-guide may comprise a material having an optically filtering dye ora material which inherently filters one or more wavelengths of light.For example, a light-absorptive dye, many of which are well-known in theart, may be integrated within or coated on top a polycarbonate oracrylic sheet. Similarly, a light-absorptive dye may be integratedwithin a resin which may then be molded into one or more light guides. Afew non-limiting examples of an inherently filtering material includessapphire, which absorbs some infrared (IR) wavelengths, or glass, whichabsorbs some ultraviolet (UV) wavelengths. However, various types offiltering material may be utilized, without limitation.

In some embodiments, a light guide 119 may be surrounded or partiallysurrounded by a cladding material 121 (FIG. 30) that is configured toblock light from an external source from entering the light guide 119and/or at least partially confine light within the light guide 119. Thecladding material 121 may be a light blocking material and/or a lightreflective material. For example, the cladding material 121 may be adark (e.g., black, etc.) or silver (or other reflective color) coating,or a texturized light-scattering material on one or more portions of thesurface of the light guide 119.

FIGS. 26-29 illustrate various light guide configurations that may beutilized within headsets and wearable sensor modules (e.g., sensormodules that can be attached to earlobes, fingers, wrists, ankles, toes,other digits, other skin regions, etc.), according to some embodimentsof the present invention. For example, when used in conjunction withApplicants' signal extraction technology, these sensor modules mayfunction well when embedded within a wrist strap, wrist watch, anklebracelet, armband, chest strap, and other form-factors that can engagethe sensor module with the skin. Although the light guides 119 in FIGS.26, 27 and 29 are illustrated as having the same length, it isunderstood that embodiments of the present invention are not limited tolight guides 119 having the same length.

In FIG. 26, an optical emitter 24 and optical detector 26 are attachedto a base 50 and light blocking material 21 is positioned between theoptical emitter 24 and detector 26 such that the optical emitter 24 anddetector 26 are not in direct optical communication with each other. Insome embodiments, the light blocking material 21 may completely blocklight from the optical emitter from directly reaching the opticaldetector 26. In other embodiments, the light blocking material 21 maypartially block light from the optical emitter from directly reachingthe optical detector 26.

As illustrated in FIG. 26, a respective light guide 119 is in opticalcommunication with the optical emitter 24 and optical detector 26.However, in other embodiments, a plurality of light guides 119 may be inoptical communication with the light emitter 24 and/or light detector26. It should be noted that the free end 119 c of the light guide 119may branch out to two or more “legs” that may be used to couple withmany different parts of the body, such as multiple parts of the ear.Monitoring multiple regions of the ear may be beneficial as described inco-owned and copending U.S. Patent Application Publication No.2010/0217098, which is incorporated herein by reference in its entirety.

As illustrated in FIG. 27, a headset or sensor module may include aplurality of optical emitters 24 and/or optical detectors 26 with arespective light guide in optical communication therewith. It should benoted that the light guides 119 may be used to couple with manydifferent parts of the body, such as multiple parts of the ear.

As illustrated in FIG. 28, a single light guide 119 may be in opticalcommunication with an optical emitter 24 and with an optical detector26.

As illustrated in FIG. 29, optical coupling material 120 may be appliedto one or both of the optical emitter 24 and optical detector 26 of aheadset or sensor module. A light guide 119 is in optical communicationwith the optical emitter 24 and optical detector 26 via the opticalcoupling material 120. The optical coupling material 120 may comprise amaterial that effectively couples light from the optical emitter 24 tothe light guide 119 or from the light guide 119 to the optical detector26. Examples of suitable materials include, but are not limited to,glue, tape, resin, gel, filler material, molded material or the like. Afew non-limiting examples of a molded material may include, but are notlimited to, silicone, plastic, polymer, or polyurethane part that isform-fitted to matingly engage the light guide and the emitter and/ordetector. A benefit of molded, form-fitted optical coupling is that itmay be routinely attached/detached due to the non-permanent interface.This may be useful for the case where a light guide 119 may need to beroutinely attached/detached from an emitter 24 and/or detector 26. Twoattractive properties of suitable optical coupling materials mayinclude: 1) a refractive index that matches or closely matches that ofthe emitter, detector, or light guide and 2) providing a solid interfacebetween the coupled elements without an air gap in between.

In some embodiments of the present invention, such as illustrated inFIGS. 24A-24B and 25A-25B, an optical emitter 24 and optical detector 26are attached to or disposed within the housing 14. However, in otherembodiments of the present invention, an optical emitter 24 and/oroptical detector 26 can be located remotely from the housing 14. Forexample, as illustrated in FIG. 32, the optical emitter 24 and opticaldetector 26 may be located on a headband or other structure that is apart of a headset. In the illustrated embodiment of FIG. 32, the headset100 is a stereo headset having a pair of earbuds 30. An optical emitter24 and optical detector 26 are located on the headband 100 h of theheadset 100. In some embodiments with wired headphones, the emitterand/or detector may be located on a “medallion” or a mobile device (suchas a smartphone) itself, with the associated light guide(s) running inbetween the headphone and the medallion or mobile device.

A pair of elongated light guides 119, such as illustrated in FIG. 31,are in optical communication with the optical emitter 24 and opticaldetector 26 via proximal end portions 119 b and extend from the opticalemitter 24 and optical detector 26 to an earbud 30. The earbud 30includes a pair of apertures 30 a formed therethrough. Each light guidedistal end is positioned within a respective earbud aperture 30 a suchan exposed end surface 119 c thereof is configured to engage (or bepositioned adjacent) a portion of an ear of a subject. As such, thelight guide 119 in optical communication with the optical emitter 24 candeliver light from the optical emitter 24 into an ear region of thesubject, and the light guide 119 in optical communication with theoptical detector 26 can collect light from the ear region of the subjectand deliver collected light to the optical detector 26. It should benoted that the distal free end surface 119 c of the light guide 119 maycomprise a variety of shapes, as discussed previously, more thanexemplarily shown in FIG. 33.

The optical emitter 24 and optical detector 26 may be embedded withinthe headband 100 h (also referred to as a “back band” as this maytypically be worn behind the head), or may be located external to theheadband 100 h. In addition, the elongated light guides 119 incommunication with the optical emitter 24 and optical detector 26 may beembedded within the headband 100 h. However, in some embodiments of thepresent invention, the elongated light guides 119 may be external or atleast partially external to the headband 110 h.

Though many of the drawings herein show emitters and detectors in onlyone earbud, it should be understood that the emitters and detectors maybe in multiple earbuds, left and right, for use in biometric monitoring.Certain benefits may be realized by incorporating light guides from theheadband to both earbuds. For example, having emitters and detectors inmultiple earbuds may enable the ability to measure the transit timebetween blood pulses on the right and left sides of the head, and thismeasurement may be used to estimate the blood pressure of the person.For example, the blood moving from the carotid artery on the right ofthe head and moving to the left of the head may be modulated in part bythe blood pressure, and thus by measuring the time difference betweenright and left blood pulses, and by integrating this measurement into aformula relating pulse transit time and blood pressure, potentiallyfurther including a relationship for arterial stiffness, a method ofdetermining blood pressure may be implemented. Additionally, thedifference between the intensity of the pulsatile blood flow signals,namely the difference in amplitude of the AC blood flow pulses, betweenthe right and left sides of the head may be directly proportional to theblood pressure of the person wearing the headset. A suitable stereoheadset configuration for providing this type of functionality maycomprise a light guiding method as shown in FIG. 27, with a plurality ofemitters and detectors.

FIG. 35 illustrates the headset 10 of FIG. 1 with light guides 119 inthe earbud housing cover 18, according to some embodiments of thepresent invention. Each light guide 119 is configured to be in opticalcommunication with a respective one of the optical emitter 24 andoptical detectors 26. In this embodiment, the earbud housing cover 18may be substantially opaque. As such, the only light transmissive pathsare via the light guides 119. However, embodiments of the presentinvention represented by FIG. 35 do not require that the housing cover18 be opaque.

FIGS. 36-40 illustrate a headset 10 incorporating light guides 119according to other embodiments of the present invention. The headsethousing 14 includes an opaque front housing portion 14 a (FIG. 40) andan opaque rear housing portion 14 b (FIG. 40). A removable cover 18 isconfigured to be attached to and matingly engage the front housingportion 14 a. The cover 18 can be provided in various sizes, eachadapted to the shape and size of an ear of a subject. For example,covers 18 may come in large, medium, and small sizes, etc. The cover 18may be formed from a soft or elastomeric material. Examples of suitablesoft or elastomeric materials may include, but are not limited to,silicone, rubber, polymer-based materials, latex, lower durometerplastics, and the like.

The front housing portion 14 a includes a portion 14 c that has a pairof filter lenses 140 integral therewith. The cover 18 has acorresponding portion 18 a that includes a pair of light guides 119integral therewith, as illustrated. The light guides 119 aresubstantially flush with an end surface 18 b of portion 18 a in theillustrated embodiment. When the cover 18 is installed on the fronthousing portion 14 a, the light guides 119 are in alignment (i.e.,optical communication) with the filter lenses 140, as illustrated inFIG. 38.

The foregoing is illustrative of the present invention and is not to beconstrued as limiting thereof. Although a few exemplary embodiments ofthis invention have been described, those skilled in the art willreadily appreciate that many modifications are possible in the exemplaryembodiments without materially departing from the teachings andadvantages of this invention. Accordingly, all such modifications areintended to be included within the scope of this invention as defined inthe claims. The invention is defined by the following claims, withequivalents of the claims to be included therein.

That which is claimed is:
 1. A method of monitoring a subject via asensor module, wherein the sensor module includes at least one opticalemitter and at least one optical detector, a first light guide having aproximal end optically coupled to the at least one optical emitter andan opposite distal end with a free end surface, and a second light guidehaving a proximal end optically coupled to the at least one opticaldetector and an opposite distal end with a free end surface, the methodcomprising: attaching the sensor module to a body of the subject suchthat the respective distal end free end surfaces of the first and secondlight guides engage respective portions of the body of the subject;delivering light from the at least one optical emitter directly into thebody of the subject via the distal end free end surface of the firstlight guide; and collecting light directly from the body of the subjectvia the distal end free end surface of the second light guide.
 2. Themethod of claim 1, wherein the sensor module includes at least onemotion sensor, and further comprising sensing motion information fromthe subject via the at least one motion sensor.
 3. The method of claim2, wherein the sensor module includes at least one signal processor, andfurther comprising removing, via the at least one signal processor,motion artifacts from signals produced by the at least one opticaldetector in response to signals produced by the at least one motionsensor.
 4. The method of claim 1, wherein the sensor module includes atleast one signal processor, and further comprising processing, via theat least one signal processor, signals produced by the at least oneoptical detector to detect and/or measure physiological informationabout the subject.
 5. The method of claim 1, wherein the sensor moduleincludes at least one signal processor and at least one motion sensor,and further comprising processing, via the at least one signalprocessor, signals produced by the at least one optical detector andsignals produced by the at least one motion sensor to determine subjectheart rate and respiration rate.
 6. The method of claim 1, wherein thesensor module is included within an earbud of a headset, whereinattaching the sensor module to a body of the subject comprisespositioning the earbud within an ear of the subject such that therespective distal end free end surfaces of the first and second lightguides engage respective portions of the ear, wherein delivering lightfrom the at least one optical emitter directly into the body of thesubject via the distal end free end surface of the first light guidecomprises delivering light from the optical emitter into an ear region,and wherein collecting light from the body of the subject via the distalend free end surface of the second light guide comprises collectinglight from the ear region.
 7. The method of claim 6, wherein the earregion is between the anti tragus and concha of the ear.
 8. The methodof claim 1, wherein the sensor module includes a signal processor, andfurther comprising executing an adaptive filter algorithm via the signalprocessor to remove noise from signals produced by the at least oneoptical emitter.
 9. A method of monitoring a subject via a headset,wherein the headset includes at least one optical emitter, at least oneoptical detector, a first light guide having a proximal end opticallycoupled to the at least one optical emitter and an opposite distal end,a second light guide having a proximal end optically coupled to the atleast one optical detector and an opposite distal end, and a housingconfigured to be positioned within an ear of a subject, the methodcomprising: positioning the housing within the ear of the subject suchthat the housing is supported by the ear and such that the first andsecond light guide distal ends are not located within the ear canal;delivering light from the at least one optical emitter into the ear in afirst direction away from the ear canal via the first light guide distalend; and collecting light from the ear in a second direction away fromthe ear canal via the second light guide distal end.
 10. The method ofclaim 9, wherein delivering light from the at least one optical emitterinto the ear comprises delivering light to a region of the ear betweenthe anti tragus and concha.
 11. The method of claim 9, wherein the firstand second directions are substantially parallel.
 12. The method ofclaim 9, wherein the headset includes at least one motion sensor, andfurther comprising sensing motion information from the subject via theat least one motion sensor.
 13. The method of claim 12, wherein theheadset includes at least one signal processor, and further comprisingremoving, via the at least one signal processor, motion artifacts fromsignals produced by the at least one optical detector in response tosignals produced by the at least one motion sensor.
 14. The method ofclaim 9, wherein the headset includes at least one signal processor, andfurther comprising processing, via the at least one signal processor,signals produced by the at least one optical detector to detect and/ormeasure physiological information about the subject.
 15. The method ofclaim 9, wherein the headset includes at least one signal processor andat least one motion sensor, and further comprising processing, via theat least one signal processor, signals produced by the at least oneoptical detector and signals produced by the at least one motion sensorto determine subject heart rate and respiration rate.
 16. The method ofclaim 9, wherein the sensor module includes a signal processor, andfurther comprising executing an adaptive filter algorithm via the signalprocessor to remove noise from signals produced by the at least oneoptical emitter.
 17. A method of monitoring a subject via a headset,wherein the headset includes at least one optical emitter, at least oneoptical detector, at least one signal processor, a first light guidehaving a proximal end optically coupled to the at least one opticalemitter and an opposite distal end with a free end surface, a secondlight guide having a proximal end optically coupled to the at least oneoptical detector and an opposite distal end with a free end surface, anda housing configured to be positioned within an ear of a subject, theear having an anti tragus and a concha, the method comprising:positioning the housing within the ear of the subject such that thehousing is supported by the ear and such that the respective distal endfree end surfaces of the first and second light guides engage respectiveportions of the ear between the anti tragus and concha; delivering lightfrom the at least one optical emitter into a region of the ear betweenthe anti tragus and concha via the distal end free end surface of thefirst light guide; collecting light from the region of the ear betweenthe anti tragus and concha via the distal end free end surface of thesecond light guide; and processing, via the at least one signalprocessor, signals produced by the at least one optical detector todetermine subject heart rate and respiration rate.
 18. The method ofclaim 17: wherein processing the signals produced by the at least oneoptical detector to determine subject heart rate and respiration ratecomprises utilizing at least one digital filter and at least one peakfinding algorithm.